JP2013125891A - Photoelectric conversion element and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric conversion element which can improve insulation properties.SOLUTION: A photoelectric conversion element 100 comprises: an n-type single crystal silicon substrate 1; a passivation film 2; p-type amorphous films 11-1m; n-type amorphous films 21-2m-1; semiconductor thin films 31-3n; and electrodes 41-4m, 51-5m. The p-type amorphous films 11-1m and the n-type amorphous films 21-2m-1 are alternately arranged in an in-plane direction with contacting a rear face of the n-type single crystal silicon substrate 1. The semiconductor thin films 31-3n contact the p-type amorphous films 11-1m and the n-type amorphous films 21-2m-1 and arranged between the p-type amorphous films 11-1m and the n-type amorphous films 21-2m-1. The electrodes 41-4m are arranged to contact the p-type amorphous films 11-1m, respectively, and the electrodes 51-5m -1 are arranged to contact the n-type amorphous films 21-2m-1, respectively.

Description

  The present invention relates to a photoelectric conversion element and a manufacturing method thereof.

  The back contact solar cell has a high efficiency by forming a pn junction and an electrode on the light receiving surface side on the back surface, thereby eliminating shadows from the electrode on the light receiving surface side and absorbing more sunlight. Solar cell to get.

  In this solar cell, the pn junction is formed by thermal diffusion (Patent Document 1).

  A solar cell in which a pn junction is formed on the back surface by a method other than thermal diffusion has also been proposed (Patent Document 2). In this solar cell, i-type amorphous silicon (a-Si) and n-type a-Si are sequentially laminated on the back surface of the semiconductor substrate, and a part of the laminated i-type a-Si and n-type a-Si is removed. The removed part has a structure in which i-type a-Si and p-type a-Si are sequentially laminated. In this solar cell, p-type a-Si is separated from n-type a-Si by i-type a-Si.

JP 2006-523025 A JP 2010-80887 A

  However, in the solar cell described in Patent Document 2, the separation of p-type a-Si and n-type a-Si is performed by i-type a-Si, and the film thickness of i-type a-Si is very high. Since it is thin, there exists a problem that insulation is low.

  Therefore, according to the embodiment of the present invention, a photoelectric conversion element capable of improving insulation is provided.

  Moreover, according to this Embodiment, the manufacturing method of the photoelectric conversion element which can improve insulation is provided.

  According to the embodiment of the present invention, the photoelectric conversion element includes a semiconductor substrate, first and second amorphous films, and a semiconductor thin film. The semiconductor substrate is made of single crystal silicon having the first conductivity type. The first amorphous film is provided on one surface side of the semiconductor substrate and has a second conductivity type opposite to the first conductivity type. The second amorphous film is provided on one surface side of the semiconductor substrate adjacent to the first amorphous film in the in-plane direction of the semiconductor substrate, and has the first conductivity type. The semiconductor thin film is provided between the first amorphous film and the second amorphous film, and has a larger optical band gap than both the first and second amorphous films.

  In addition, according to the embodiment of the present invention, a method for manufacturing a photoelectric conversion element includes a second opposite to the first conductivity type on one surface of a semiconductor substrate made of single crystal silicon having the first conductivity type. And a second step of forming a semiconductor thin film so as to cover both ends of the first amorphous film in the in-plane direction of the semiconductor substrate. A step of depositing a semiconductor thin film and a second amorphous film having a first conductivity type on one surface of the semiconductor substrate adjacent to the first amorphous film in an in-plane direction of the semiconductor substrate; The semiconductor thin film has an optical band gap larger than both the first and second amorphous films.

  In the photoelectric conversion element according to the embodiment of the present invention, the semiconductor thin film having an optical band gap larger than that of the first and second amorphous films includes the first amorphous film and the second amorphous film. Between. As a result, it becomes difficult for carriers to flow between the first amorphous film and the second amorphous film.

  Therefore, insulation can be improved.

  In the method of manufacturing a photoelectric conversion element according to the embodiment of the present invention, a semiconductor thin film is formed so as to cover both ends of the first amorphous film, and the second amorphous film is formed on the semiconductor thin film. accumulate. As a result, the second amorphous film does not come into contact with the first amorphous film, and carriers hardly flow between the first amorphous film and the second amorphous film.

  Therefore, insulation can be improved.

It is sectional drawing which shows the structure of the photoelectric conversion element by Embodiment 1 of this invention. It is a 1st process drawing which shows the manufacturing method of the photoelectric conversion element shown in FIG. It is a 2nd process figure which shows the manufacturing method of the photoelectric conversion element shown in FIG. FIG. 4 is a third process diagram illustrating a method for manufacturing the photoelectric conversion element illustrated in FIG. 1. FIG. 5 is a cross-sectional view showing a configuration of another photoelectric conversion element according to Embodiment 1. FIG. 6 is a cross-sectional view illustrating a configuration of still another photoelectric conversion element according to Embodiment 1. FIG. 6 is a cross-sectional view illustrating a configuration of still another photoelectric conversion element according to Embodiment 1. 6 is a cross-sectional view illustrating a configuration of a photoelectric conversion element according to Embodiment 2. FIG. It is sectional drawing which shows the structure of the other photoelectric conversion element by Embodiment 2. FIG. FIG. 6 is a cross-sectional view showing a configuration of still another photoelectric conversion element according to Embodiment 2. FIG. 6 is a cross-sectional view showing a configuration of still another photoelectric conversion element according to Embodiment 2.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  In this specification, the “amorphous phase” refers to a state in which silicon (Si) atoms and the like are randomly arranged. Moreover, although amorphous silicon is described as “a-Si”, this notation actually means that hydrogen (H) atoms are included. Amorphous silicon carbide (a-SiC), amorphous silicon oxide (a-SiO), amorphous silicon nitride (a-SiN), amorphous silicon carbon nitride (a-SiCN), amorphous silicon germanium (a-SiGe) and amorphous germanium Similarly, (a-Ge) means that an H atom is contained.

[Embodiment 1]
1 is a cross-sectional view showing a configuration of a photoelectric conversion element according to Embodiment 1 of the present invention. Referring to FIG. 1, a photoelectric conversion element 100 according to Embodiment 1 of the present invention includes an n-type single crystal silicon substrate 1, a passivation film 2, and p-type amorphous films 11 to 1m (m is 2 or more). Integer), n-type amorphous films 21 to 2m-1, semiconductor thin films 31 to 3n (n is an integer satisfying n = 2 (m-1)), electrodes 41 to 4m, and 51 to 5m-1. Is provided.

  The n-type single crystal silicon substrate 1 has, for example, a (100) plane orientation and a specific resistance of 0.1 to 1.0 Ω · cm. The n-type single crystal silicon substrate 1 has a thickness of 100 to 300 μm, for example, and preferably has a thickness of 100 to 200 μm.

The passivation film 2 is made of, for example, silicon dioxide (SiO ₂ ), and is provided in contact with the light incident side surface of the n-type single crystal silicon substrate 1. And the passivation film 2 has a film thickness of 100 nm, for example.

Each of p-type amorphous films 11 to 1 m is made of an amorphous phase, and is provided in contact with the surface of n-type single crystal silicon substrate 1 opposite to the light incident side. Each of the p-type amorphous films 11 to 1m is made of, for example, p-type a-Si and has a film thickness of, for example, 10 nm. The p-type amorphous films 11 to 1 m are arranged at a desired interval in the in-plane direction of the n-type single crystal silicon substrate 1. Furthermore, the boron (B) concentration in each of the p-type amorphous films 11 to 1 m is, for example, 5 × 10 ¹⁹ cm ⁻³ .

The n-type amorphous films 21 to 2m−1 are made of an amorphous phase, and are respectively between the p-type amorphous films 11 and 12, between the p-type amorphous films 12 and 13,. Between the type amorphous films 1m-1 and 1m, the semiconductor thin films 31, 32; 33, 34;. Each of the n-type amorphous films 21 to 2m−1 is made of, for example, n-type a-Si, and has a film thickness of, for example, 10 nm. Further, the phosphorus (P) concentration in each of the n-type amorphous films 21 to 2m−1 is, for example, 5 × 10 ¹⁹ cm ⁻³ .

  Each of the semiconductor thin films 31 to 3n is made of, for example, i-type a-SiC. Each of the semiconductor thin films 31 to 3n has a film thickness of, for example, several tens of nm or more, and generally has a film thickness that carriers (electrons and holes) cannot tunnel. The semiconductor thin film 31 is disposed in contact with the p-type amorphous film 11, the n-type amorphous film 21, and the n-type single crystal silicon substrate 1, and the semiconductor thin films 32 and 33 are formed of the p-type amorphous film 12. The semiconductor thin films 34 and 35 are arranged in contact with the n-type amorphous films 21 and 22 and the n-type single crystal silicon substrate 1, and the semiconductor thin films 34 and 35 are formed of the p-type amorphous film 13, the n-type amorphous films 22 and 23, and the n-type amorphous films 22 and 23, respectively. In the same manner, the semiconductor thin films 3n-2 and 3n-1 are composed of a p-type amorphous film 1m-1 and n-type amorphous films 2m-2 and 2m. -1 and n-type single crystal silicon substrate 1 and semiconductor thin film 3n is arranged in contact with p-type amorphous film 1m, n-type amorphous film 2m-1 and n-type single crystal silicon substrate 1 Is done.

  The electrodes 41 to 4m are provided in contact with the p-type amorphous films 11 to 1m, respectively. The electrodes 51-5m-1 are provided in contact with the n-type amorphous films 21-2m-1, respectively. And each of the electrodes 41-4m and 51-5m-1 consists of silver (Ag), for example.

  The p-type amorphous films 11-1m and the n-type amorphous films 21-2m-1 have the same length in the direction perpendicular to the paper surface of FIG. The area occupation ratio, which is the ratio of the entire area of the p-type amorphous film 11 to 1 m to the area of the n-type single crystal silicon substrate 1, is 60 to 93%. The area occupation ratio, which is the ratio of the entire area of 2m−1 to the area of the n-type single crystal silicon substrate 1, is 5 to 20%.

  As described above, the area occupancy of the p-type amorphous films 11 to 1m is made larger than the area occupancy of the n-type amorphous films 21 to 2m-1 by photoexcitation in the n-type single crystal silicon substrate 1. The separated electrons and holes are easily separated by the pn junction (p-type amorphous film 11 to 1 m / n-type single crystal silicon substrate 1), and the contribution ratio of photoexcited electrons and holes to power generation is increased. Because.

  2-4 is a 1st-3rd process drawing which respectively shows the manufacturing method of the photoelectric conversion element 100 shown in FIG.

  A method for manufacturing the photoelectric conversion element 100 will be described. The photoelectric conversion element 100 is manufactured by a plasma CVD method mainly using a plasma apparatus.

  The plasma apparatus includes a preparation chamber, reaction chambers CB1 to CB3, an extraction chamber, a matching unit, and an RF power source. The charging chamber, the reaction chambers CB1 to CB3, and the take-out chamber are arranged in series. A partition valve is used to partition between the charging chamber and the reaction chamber CB1, between the reaction chamber CB1 and the reaction chamber CB2, between the reaction chamber CB2 and the reaction chamber CB3, and between the reaction chamber CB3 and the take-out chamber. It has been. Further, the plasma apparatus is provided with a transport mechanism for sequentially transporting the single crystal silicon substrate from the preparation chamber to the reaction chamber CB1, the reaction chamber CB2, the reaction chamber CB3, and the take-out chamber.

The charging chamber includes a heating mechanism and an exhaust mechanism. The heating mechanism raises the temperature of the single crystal silicon substrate to a predetermined temperature. The exhaust mechanism exhausts the gas in the preparation chamber, and sets the ultimate pressure in the preparation chamber to, for example, 1 × 10 ⁻⁵ Pa or less.

Each of the reaction chambers CB1 to CB3 includes a parallel plate electrode, a heating mechanism, and an exhaust mechanism. The heating mechanism raises the temperature of the single crystal silicon substrate to a predetermined temperature. The exhaust mechanism exhausts the gases in the reaction chambers CB1 to CB3, and sets the ultimate pressure in the reaction chambers CB1 to CB3 to, for example, 1 × 10 ⁻⁵ Pa or less. The parallel plate electrodes are connected to an RF power source through a matching unit. The reaction chamber CB1 is a reaction chamber for depositing p-type a-Si, the reaction chamber CB2 is a reaction chamber for depositing i-type a-SiC, and the reaction chamber CB3 is an n-type a-a. A reaction chamber for depositing Si.

The take-out chamber includes an exhaust mechanism. The exhaust mechanism exhausts the gas in the extraction chamber and sets the ultimate pressure in the extraction chamber to, for example, 1 × 10 ⁻⁵ Pa or less.

  Each exhaust mechanism of the charging chamber, the reaction chambers CB1 to CB3, and the take-out chamber includes a turbo molecular pump, a mechanical booster pump, and a rotary pump. The turbo molecular pump, the mechanical booster pump and the rotary pump are serially connected to the charging chamber, the reaction chambers CB1 to CB3 and the extraction chamber, respectively, so that the turbo molecular pump is closest to the charging chamber, the reaction chambers CB1 to CB3 and the extraction chamber. It is connected to. Each exhaust mechanism exhausts the gas in the charging chamber, reaction chambers CB1 to CB3, and the extraction chamber with a turbo molecular pump, a mechanical booster pump, and a rotary pump, respectively, or is charged with a mechanical booster pump and a rotary pump, respectively. The gases in the chamber, reaction chambers CB1 to CB3 and the extraction chamber are exhausted.

  The RF power source applies, for example, RF power of 13.56 MHz to the parallel plate electrodes of the reaction chambers CB1 to CB3 via the matching unit.

  When the manufacture of the photoelectric conversion element 100 is started, the n-type single crystal silicon substrate 1 is ultrasonically cleaned with ethanol or the like and degreased, and then the n-type single crystal silicon substrate 1 is immersed in hydrofluoric acid to be n-type. The natural oxide film formed on the surface of the single crystal silicon substrate 1 is removed, and the surface of the n-type single crystal silicon substrate 1 is terminated with hydrogen (see step (a) in FIG. 2).

When the cleaning of the n-type single crystal silicon substrate 1 is completed, the n-type single crystal silicon substrate 1 is put in an oxidation furnace, and the n-type single crystal silicon substrate 1 is thermally oxidized at a temperature of 1000 ° C. in an oxygen atmosphere. In this case, the oxidation time is, for example, 30 minutes. Then, the SiO ₂ formed on one surface and the end surface of the n-type single-crystalline silicon substrate 1 is removed by hydrofluoric acid to form a passivation film 2 made of SiO ₂ on one surface of the n-type single-crystalline silicon substrate 1 (See step (b) in FIG. 2).

  Then, the n-type single crystal silicon substrate 1 / passivation film 2 is disposed on the substrate holder in the preparation chamber of the plasma apparatus.

And the exhaust mechanism of the preparation chamber exhausts the gas in the preparation chamber to 1 × 10 ⁻⁵ Pa or less, and the heating mechanism of the preparation chamber sets the temperature of the n-type single crystal silicon substrate 1 / passivation film 2 to 200 ° C. Heat the substrate holder so that it does. Further, the heating mechanism of the reaction chambers CB1 to CB3 also heats the substrate holder so that the temperature of the n-type single crystal silicon substrate 1 / passivation film 2 is set to 200.degree.

  When the temperature of the n-type single crystal silicon substrate 1 / passivation film 2 reaches 200 ° C., the partition valve between the charging chamber and the reaction chamber CB1 is opened, and the n-type single crystal silicon substrate 1 / passivation film 2 is charged It is conveyed from the chamber to the reaction chamber CB1.

  Table 1 shows the flow rates of the material gases when forming the p-type amorphous films 11 to 1m, the n-type amorphous films 21 to 2m-1, and the semiconductor thin films 31 to 3n.

When the n-type single crystal silicon substrate 1 / passivation film 2 is transferred to the reaction chamber CB1, 2 sccm of silane (SiH ₄ ) gas, 42 sccm of hydrogen (H ₂ ) gas, and hydrogen diluted 12 sccm of diborane (B ₂ H ₆ ) gas is allowed to flow into the reaction chamber CB1, and the pressure in the reaction chamber CB1 is set in the range of 13.3 Pa to 665 Pa. The RF power source applies RF power in the range of 16 to 80 mW / cm ² to the parallel plate electrodes through the matching unit. As a result, plasma is generated in the reaction chamber CB1, and the p-type amorphous film 20 made of p-type a-Si is on the surface of the n-type single crystal silicon substrate 1 (= the side opposite to the surface on which the passivation film 2 is formed). (See step (c) in FIG. 2). The concentration of B ₂ H ₆ gas diluted with hydrogen is 0.1%.

When the thickness of the p-type amorphous film 20 reaches 10 nm, the application of RF power to the parallel plate electrodes in the reaction chamber CB1 is stopped, and the reaction chamber CB1 of SiH ₄ gas, H ₂ gas, and B ₂ H ₆ gas is stopped. And the reaction chamber CB1 is evacuated to 1 × 10 ⁻⁵ Pa or less by an exhaust mechanism. Then, the gate valve is opened and the p-type amorphous film 20 / n-type single crystal silicon substrate 1 / passivation film 2 is transferred from the reaction chamber CB1 to the take-out chamber, and the p-type amorphous film 20 / n-type single crystal silicon is transferred. The substrate 1 / passivation film 2 is cooled to room temperature and then taken out.

  Then, a resist is applied to the entire surface of the p-type amorphous film 20 of the extracted p-type amorphous film 20 / n-type single crystal silicon substrate 1 / passivation film 2, and the applied resist is patterned by photolithography. Then, a resist pattern 30 is formed (see step (d) in FIG. 2).

  Thereafter, the p-type amorphous film 20 is etched by dry etching or wet etching using the resist pattern 30 as a mask to form p-type amorphous films 11 to 1m (see step (e) in FIG. 2).

  When the p-type amorphous films 11 to 1m are formed, the p-type amorphous films 11 to 1m / n-type single crystal silicon substrate 1 / passivation film 2 on the p-type amorphous films 11 to 1m side is washed with hydrofluoric acid. Then, the p-type amorphous film 11 to 1 m / n-type single crystal silicon substrate 1 / passivation film 2 is disposed on the substrate holder in the preparation chamber of the plasma apparatus.

And the exhaust mechanism of the preparation chamber exhausts the gas in the preparation chamber to 1 × 10 ⁻⁵ Pa or less, and the heating mechanism of the preparation chamber is the p-type amorphous film 11 to 1 m / n type single crystal silicon substrate 1 / The substrate holder is heated so that the temperature of the passivation film 2 is set to 200 ° C.

  When the temperature of the p-type amorphous film 11 to 1 m / n type single crystal silicon substrate 1 / passivation film 2 reaches 200 ° C., the p-type amorphous film 11 to 1 m / n type single crystal silicon substrate 1 / passivation film 2 is transferred from the preparation chamber to the reaction chamber CB2.

When the p-type amorphous film 11 to 1 m / n-type single crystal silicon substrate 1 / passivation film 2 is transferred to the reaction chamber CB2, 2 sccm of SiH ₄ gas, 42 sccm of H ₂ gas, and 1.6 sccm of methane (CH ₄ ) gas is allowed to flow into the reaction chamber CB2 (see Table 1), and the pressure in the reaction chamber CB2 is set in the range of 13.3 Pa to 665 Pa. The RF power source applies RF power in the range of 16 to 80 mW / cm ² to the parallel plate electrodes through the matching unit. Thereby, plasma is generated in the reaction chamber CB2, and the semiconductor thin film 40 made of i-type a-SiC is deposited on the surfaces of the p-type amorphous films 11 to 1m and the n-type single crystal silicon substrate 1 (FIG. 3). Step (f)).

When the thickness of the semiconductor thin film 40 reaches several tens of nm or more, the application of RF power to the parallel plate electrodes in the reaction chamber CB2 is stopped and the supply of SiH ₄ gas, H ₂ gas, and CH ₄ gas to the reaction chamber CB2 is stopped. And the reaction chamber CB2 is evacuated to 1 × 10 ⁻⁵ Pa or less by an exhaust mechanism. Then, the gate valve is opened, and the semiconductor thin film 40 / p-type amorphous film 11 to 1 m / n-type single crystal silicon substrate 1 / passivation film 2 is transferred from the reaction chamber CB2 to the take-out chamber. Then, the semiconductor thin film 40 / p-type amorphous film 11 to 1m / n-type single crystal silicon substrate 1 / passivation film 2 is cooled to room temperature and taken out from the take-out chamber.

  Thereafter, a resist is applied on the semiconductor thin film 40 of the semiconductor thin film 40 / p-type amorphous film 11 to 1m / n type single crystal silicon substrate 1 / passivation film 2, and the applied resist is patterned by photolithography. A resist pattern 50 is formed (see step (g) in FIG. 3).

  Thereafter, the semiconductor thin film 40 is etched by dry etching or wet etching using the resist pattern 50 as a mask to form semiconductor thin films 31 to 3n (see step (h) in FIG. 3).

  The semiconductor thin films 31 to 3n / p type amorphous film 11 to 1m / n type single crystal silicon substrate 1 / the semiconductor thin films 31 to 3n side of the passivation film 2 are washed with hydrofluoric acid, and the semiconductor thin films 31 to 3n / p A type amorphous film 11 to 1 m / n type single crystal silicon substrate 1 / passivation film 2 is arranged on a substrate holder in a preparation chamber of a plasma apparatus.

After that, the evacuation mechanism of the preparation chamber exhausts the gas in the preparation chamber to 1 × 10 ⁻⁵ Pa or less, and the heating mechanism of the preparation chamber is the semiconductor thin film 31 to 3 n / p type amorphous film 11 to 1 m / n type. The substrate holder is heated so that the temperature of the single crystal silicon substrate 1 / passivation film 2 is set to 200.degree.

  When the temperature of the semiconductor thin films 31 to 3n / p type amorphous film 11 to 1m / n type single crystal silicon substrate 1 / passivation film 2 reaches 200 ° C., the semiconductor thin films 31 to 3n / p type amorphous film 11 to 11 The 1 m / n type single crystal silicon substrate 1 / passivation film 2 is transferred from the preparation chamber to the reaction chamber CB3.

When the semiconductor thin films 31 to 3n / p type amorphous film 11 to 1m / n type single crystal silicon substrate 1 / passivation film 2 are transferred to the reaction chamber CB3, 20 sccm of SiH ₄ gas, 150 sccm of H ₂ gas, Then, 50 sccm of phosphine (PH ₃ ) gas diluted with hydrogen is allowed to flow into the reaction chamber CB3 (see Table 1), and the pressure of the reaction chamber CB3 is set in the range of 13.3 Pa to 665 Pa. The RF power source applies RF power in the range of 16 to 80 mW / cm ² to the parallel plate electrodes through the matching unit. As a result, plasma is generated in the reaction chamber CB3, and the n-type amorphous film 60 made of n-type a-Si becomes the semiconductor thin films 31 to 3n, the p-type amorphous films 11 to 1m, and the n-type single crystal silicon substrate. 1 (see step (i) in FIG. 3). The concentration of PH ₃ gas diluted with hydrogen is 0.2%.

When the thickness of the n-type amorphous film 60 reaches 10 nm, the application of RF power to the parallel plate electrodes in the reaction chamber CB3 is stopped, and SiH ₄ gas, H ₂ gas, and PH ₃ gas are supplied to the reaction chamber CB3. The supply is stopped, and the reaction chamber CB3 is evacuated to 1 × 10 ⁻⁵ Pa or less by an exhaust mechanism. Then, the gate valve is opened, and the n-type amorphous film 60 / semiconductor thin film 31-3n / p-type amorphous film 11-1m / n-type single crystal silicon substrate 1 / passivation film 2 is transferred from the reaction chamber CB3 to the take-out chamber. Transport. Then, the n-type amorphous film 60 / semiconductor thin film 31-3n / p-type amorphous film 11-1m / n-type single crystal silicon substrate 1 / passivation film 2 is cooled to room temperature and taken out from the take-out chamber.

  Thereafter, a resist is applied on the n-type amorphous film 60 of the n-type amorphous film 60 / semiconductor thin film 31-3n / p-type amorphous film 11-1m / n-type single crystal silicon substrate 1 / passivation film 2. Then, the applied resist is patterned by photolithography to form a resist pattern 70 (see step (j) in FIG. 4).

  Thereafter, the n-type amorphous film 60 is etched by dry etching or wet etching using the resist pattern 70 as a mask to form n-type amorphous films 21 to 2m−1 (see step (k) in FIG. 4).

  Subsequently, Ag is vapor-deposited on the n-type amorphous films 21 to 2m-1 and the p-type amorphous films 11 to 1m side, and the deposited Ag is patterned by photolithography and etching to form electrodes 41 to 4m, 51-5m-1. Thus, the photoelectric conversion element 100 is completed (see step (l) in FIG. 4).

  In the photoelectric conversion element 100, when sunlight is irradiated onto the photoelectric conversion element 100 from the passivation film 2 side, electrons and holes are photoexcited in the n-type single crystal silicon substrate 1.

  Even if the photoexcited electrons and holes are diffused to the passivation film 2 side, they are not easily recombined by the passivation effect of the n-type single crystal silicon substrate 1 by the passivation film 2, and the p-type amorphous films 11 to 1m and n Diffusion to the type amorphous film 21-2m-1 side.

  Then, the electrons and holes diffused toward the p-type amorphous films 11 to 1m and the n-type amorphous films 21 to 2m-1 are transferred to the p-type amorphous films 11 to 1m / n-type single crystal silicon substrate 1. (= Pn junction) is separated by an internal electric field, holes reach the electrodes 41 to 4 m through the p-type amorphous films 11 to 1 m, and the electrons are n-type amorphous films 21 to 2 m−1. To reach the electrodes 51-5m-1.

  The electrons that have reached the electrodes 51 to 5m-1 reach the electrodes 41 to 4m via a load connected between the electrodes 41 to 4m and the electrodes 51 to 5m-1, and recombine with the holes.

  As described above, the photoelectric conversion element 100 converts the electrons and holes photoexcited in the n-type single crystal silicon substrate 1 into the back surface of the n-type single crystal silicon substrate 1 (= n-type single crystal silicon on which the passivation film 2 is formed). This is a back contact type photoelectric conversion element taken out from the surface opposite to the surface of the substrate 1.

In the photoelectric conversion element 100, the p-type amorphous films 11 to 1m and the n-type amorphous films 21 to 2m-1 are not in direct contact with each other, and the p-type amorphous films 11 to 1m are in contact with the n-type. Semiconductor thin films 31 to 3n made of i-type a-SiC exist between the amorphous films 21 to 2m-1. The optical band gap of i-type a-SiC is about 2.0 eV, the optical band gap of p-type a-Si constituting the p-type amorphous films 11 to 1 m is about 1.7 eV, and n-type The optical band gap of the n-type a-Si constituting the amorphous films 21 to 2m-1 is also about 1.7 eV. Moreover, p-type a-Si has a conductivity of about 1 × 10 ⁻³ (Ω · cm) ⁻¹ , and n-type a-Si has a conductivity of about 1 × 10 ⁻² (Ω · cm) ⁻¹ . Has electrical conductivity. On the other hand, i-type a-SiC has a conductivity of about 1 × 10 ⁻¹² (Ω · cm) ⁻¹ . As a result, a barrier against carriers (electrons and holes) exists between the p-type amorphous films 11 to 1m and the n-type amorphous films 21 to 2m-1, and carriers (electrons and holes) are present. Is less likely to flow between the p-type amorphous films 11-1m and the n-type amorphous films 21-2m-1 via the i-type a-SiC. Therefore, insulation can be improved.

  FIG. 5 is a cross-sectional view showing the configuration of another photoelectric conversion element according to the first embodiment. The photoelectric conversion element according to Embodiment 1 may be a photoelectric conversion element 100A illustrated in FIG.

  Referring to FIG. 5, the photoelectric conversion element 100 </ b> A is obtained by adding i-type amorphous films 61 to 6 m to the photoelectric conversion element 100 illustrated in FIG. 1, and the others are the same as the photoelectric conversion element 100.

  The i-type amorphous films 61 to 6m are made of an amorphous phase and are in contact with the n-type single crystal silicon substrate 1 and the p-type amorphous films 11 to 1m, respectively. It arrange | positions between the amorphous | non-crystalline films 11-1m. Each of the i-type amorphous films 61 to 6m is made of, for example, i-type a-Si and has a film thickness of, for example, 10 nm. Further, the i-type amorphous films 61 to 6m have the same width as the p-type amorphous films 11 to 1m in the in-plane direction of the n-type single crystal silicon substrate 1 (the left-right direction in the paper surface of FIG. 5), respectively. Have. Further, the i-type amorphous films 61 to 6m have the same length as the p-type amorphous films 11 to 1m, respectively, in the direction perpendicular to the paper surface of FIG.

  In the photoelectric conversion element 100A, the thicknesses of the n-type amorphous films 21 to 2m−1 are the thicknesses of the p-type amorphous films 11 to 1m and the i-type amorphous films 61 to 6m. And the total film thickness.

  In the photoelectric conversion element 100 </ b> A, the semiconductor thin film 31 includes a partial surface and end face of the p-type amorphous film 11, an end face of the i-type amorphous film 61, and a surface of the n-type amorphous film 21. The semiconductor thin films 32 and 33 are in contact with a part of the surface and the end face of the p-type amorphous film 12 and the i-type amorphous film 62. The semiconductor thin films 34 and 35 are in contact with the end surfaces of the n-type single crystal silicon substrate 1, the surfaces and end surfaces of the n-type amorphous films 21 and 22, and part of the surface of the n-type single crystal silicon substrate 1. A part of the surface and the end face, the end face of the i-type amorphous film 63, the surfaces and end faces of the n-type amorphous films 22 and 23, and a part of the surface of the n-type single crystal silicon substrate 1 are in contact with each other. Hereinafter, similarly, the semiconductor thin films 3n-2 and 3n-1 include a partial surface and end face of the p-type amorphous film 1m-1, an end face of the i-type amorphous film 6m-1, and an n-type. The semiconductor thin film 3n is in contact with the surface and end faces of the amorphous films 2m-2 and 2m-1 and a part of the surface of the n-type single crystal silicon substrate 1, and the semiconductor thin film 3n is part of the surface of the p-type amorphous film 1m. And the end face, the end face of the i-type amorphous film 6m, the surface and end face of the n-type amorphous film 2m-1, and a part of the surface of the n-type single crystal silicon substrate 1.

  100 A of photoelectric conversion elements are manufactured by the process (a)-process (l) shown in FIGS. In this case, in step (c) of FIG. 2, an i-type amorphous film for the i-type amorphous films 61 to 6m is deposited on the n-type single crystal silicon substrate 1 by the plasma CVD method, and then the p-type is formed. A p-type amorphous film 20 for the amorphous films 11 to 1 m is deposited on the i-type amorphous film for the i-type amorphous films 61 to 6 m by plasma CVD. The gas flow rate when depositing the i-type amorphous films for the i-type amorphous films 61 to 6 m is as shown in Table 1.

  The power generation mechanism in the photoelectric conversion element 100A is substantially the same as the power generation mechanism of the photoelectric conversion element 100, and electrons and positive ions diffused toward the p-type amorphous films 11 to 1m and the n-type amorphous films 21 to 2m-1 side. The holes are separated by an internal electric field by the p-type amorphous film 11 to 1 m / i-type amorphous film 61 to 6 m / n-type single crystal silicon substrate 1 (= pin junction), and the holes are i-type amorphous. It reaches the electrodes 41 to 4m through the material films 61 to 6m and the p-type amorphous films 11 to 1m, and the electrons pass to the electrodes 51 to 5m-1 through the n-type amorphous films 21 to 2m-1. To reach.

  The electrons that have reached the electrodes 51 to 5m-1 reach the electrodes 41 to 4m via a load connected between the electrodes 41 to 4m and the electrodes 51 to 5m-1, and recombine with the holes.

  As described above, the photoelectric conversion element 100 </ b> A allows electrons and holes photoexcited in the n-type single crystal silicon substrate 1 to be transferred to the back surface of the n-type single crystal silicon substrate 1 (= n-type single crystal silicon on which the passivation film 2 is formed). This is a back contact type photoelectric conversion element taken out from the surface opposite to the surface of the substrate 1.

  In the photoelectric conversion element 100A, an n-type amorphous film is formed between the p-type amorphous films 11 to 1m and the i-type amorphous films 61 to 6m and the n-type amorphous films 21 to 2m-1. The semiconductor thin films 31 to 3n exist so that the material films 21 to 2m-1 do not contact the p-type amorphous films 11 to 1m and the i-type amorphous films 61 to 6m. Therefore, as described in the photoelectric conversion element 100, the insulating property can be improved.

  In the photoelectric conversion element 100A, since the i-type amorphous films 61 to 6m exist between the n-type single crystal silicon substrate 1 and the p-type amorphous films 11 to 1m, the n-type single crystal silicon substrate Recombination of holes at the interface between 1 and the p-type amorphous films 11 to 1 m is suppressed. As a result, the short-circuit photocurrent increases and the conversion efficiency of the photoelectric conversion element 100A can be improved.

  The other description of the photoelectric conversion element 100A is the same as the description of the photoelectric conversion element 100.

  FIG. 6 is a cross-sectional view showing a configuration of still another photoelectric conversion element according to Embodiment 1. The photoelectric conversion element according to Embodiment 1 may be a photoelectric conversion element 100B illustrated in FIG.

  Referring to FIG. 6, photoelectric conversion element 100 </ b> B is obtained by adding i-type amorphous films 71 to 7 m−1 to photoelectric conversion element 100 shown in FIG. 1, and is otherwise the same as photoelectric conversion element 100. is there.

  The i-type amorphous films 71 to 7m-1 are made of an amorphous phase and are in contact with the n-type single crystal silicon substrate 1 and the n-type amorphous films 21 to 2m-1, respectively. 1 and n-type amorphous films 21-2m-1. Each of the i-type amorphous films 71 to 7m-1 is made of i-type a-Si, for example, and has a film thickness of 10 nm, for example. The i-type amorphous films 71 to 7m-1 have the same length as the n-type amorphous films 21 to 2m-1 in the direction perpendicular to the paper surface of FIG.

  In the photoelectric conversion element 100B, each of the p-type amorphous films 11 to 1m has a thickness of the n-type amorphous films 21 to 2m-1 and that of the i-type amorphous films 71 to 7m-1. It consists of the total film thickness with the film thickness.

  Further, in the photoelectric conversion element 100B, the semiconductor thin film 31 includes a partial surface and end face of the p-type amorphous film 11, an end face of the i-type amorphous film 71, and a surface of the n-type amorphous film 21. The semiconductor thin films 32 and 33 are in contact with a part of the surface and the end face of the p-type amorphous film 12 and the i-type amorphous film 71. , 72, the surfaces and end surfaces of the n-type amorphous films 21, 22, and a part of the surface of the n-type single crystal silicon substrate 1, and the semiconductor thin films 34, 35 are p-type amorphous films 13 partial surface and end face, i-type amorphous films 72 and 73 end faces, n-type amorphous films 22 and 23 surfaces and end faces, and n-type single crystal silicon substrate 1 partial surface. And touch. Hereinafter, in the same manner, the semiconductor thin films 3n-2 and 3n-1 include a partial surface and end face of the p-type amorphous film 1m-1 and end faces of the i-type amorphous films 7m-2 and 7m-1. The semiconductor thin film 3n is in contact with the surfaces and end faces of the n-type amorphous films 2m-2 and 2m-1 and a part of the surface of the n-type single crystal silicon substrate 1, and the semiconductor thin film 3n is formed of the p-type amorphous film 1m. Part of the surface and end face, the end face of the i-type amorphous film 7m-1, the surface and end face of the n-type amorphous film 2m-1, and the part of the surface of the n-type single crystal silicon substrate 1 Touch.

  The photoelectric conversion element 100B is manufactured by steps (a) to (l) shown in FIGS. In this case, in step (i) of FIG. 3, the i-type amorphous films for the i-type amorphous films 71 to 7m-1 are converted into p-type amorphous films 11 to 1m, semiconductor thin films 31 to 1m by plasma CVD. 3n and n-type single crystal silicon substrate 1 are deposited, and then n-type amorphous film 60 is deposited on i-type amorphous film for i-type amorphous films 71-7m-1 by plasma CVD method. Is done. The gas flow rate when depositing the i-type amorphous film for the i-type amorphous films 71 to 7m-1 is the same as the gas flow rate of the i-type amorphous films 61 to 6m shown in Table 1. .

  The power generation mechanism in the photoelectric conversion element 100B is substantially the same as the power generation mechanism of the photoelectric conversion element 100, and the electrons and positive ions diffused toward the p-type amorphous films 11 to 1m and the n-type amorphous films 21 to 2m-1 side. The holes are separated by an internal electric field by the p-type amorphous film 11 to 1 m / n-type single crystal silicon substrate 1 (= pn junction), and the holes are separated from the electrode 41 via the p-type amorphous film 11 to 1 m. -4m, and the electrons reach the electrodes 51-5m-1 through the i-type amorphous films 71-7m-1 and the n-type amorphous films 21-2m-1.

  The electrons that have reached the electrodes 51 to 5m-1 reach the electrodes 41 to 4m via a load connected between the electrodes 41 to 4m and the electrodes 51 to 5m-1, and recombine with the holes.

  As described above, the photoelectric conversion element 100B is configured to convert the electrons and holes photoexcited in the n-type single crystal silicon substrate 1 into the back surface of the n-type single crystal silicon substrate 1 (= n-type single crystal silicon on which the passivation film 2 is formed). This is a back contact type photoelectric conversion element taken out from the surface opposite to the surface of the substrate 1.

  In the photoelectric conversion element 100B, the p-type amorphous films 11 to 1m, the i-type amorphous films 71 to 7m-1, and the n-type amorphous films 21 to 2m-1 are p-type. Semiconductor thin films 31 to 3n exist so that the amorphous films 11 to 1m do not contact the i-type amorphous films 71 to 7m-1 and the n-type amorphous films 21 to 2m-1. Therefore, as described in the photoelectric conversion element 100, the insulating property can be improved.

  In the photoelectric conversion element 100B, since the i-type amorphous films 71 to 7m-1 exist between the n-type single crystal silicon substrate 1 and the n-type amorphous films 21 to 2m-1, Recombination of electrons at the interface between the single crystal silicon substrate 1 and the n-type amorphous films 21 to 2m−1 is suppressed. As a result, the short-circuit photocurrent increases and the conversion efficiency of the photoelectric conversion element 100B can be improved.

  The other description of the photoelectric conversion element 100B is the same as the description of the photoelectric conversion element 100.

  FIG. 7 is a cross-sectional view showing a configuration of still another photoelectric conversion element according to the first embodiment. The photoelectric conversion element according to Embodiment 1 may be the photoelectric conversion element 100C illustrated in FIG.

  Referring to FIG. 7, a photoelectric conversion element 100C is obtained by adding i-type amorphous films 61-6m and 71-7m-1 to the photoelectric conversion element 100 shown in FIG. The same as 100.

  The i-type amorphous films 61-6m and 71-7m-1 are as described above.

  In the photoelectric conversion element 100C, the semiconductor thin film 31 includes a partial surface and end face of the p-type amorphous film 11, end faces of the i-type amorphous films 61 and 71, and a surface of the n-type amorphous film 21. The semiconductor thin films 32 and 33 are in contact with a part of the surface and the end face of the p-type amorphous film 12 and the i-type amorphous film 62. , 71, 72, the surfaces and end surfaces of the n-type amorphous films 21, 22, and a part of the surface of the n-type single crystal silicon substrate 1, and the semiconductor thin films 34, 35 are p-type amorphous. Part of the surface and end face of the material film 13, end faces of the i-type amorphous films 63, 72 and 73, surfaces and end faces of the n-type amorphous films 22 and 23, and the n-type single crystal silicon substrate 1 Contact with some surfaces. Hereinafter, similarly, the semiconductor thin films 3n-2 and 3n-1 include a part of the surface and end face of the p-type amorphous film 1m-1, and the i-type amorphous films 6m-1, 7m-2, and 7m. -1 is in contact with the end face of n-1, the surfaces and end faces of the n-type amorphous films 2m-2 and 2m-1, and a part of the surface of the n-type single crystal silicon substrate 1, and the semiconductor thin film 3n is made of p-type amorphous. Part of the surface and end face of the material film 1m, the end faces of the i-type amorphous films 6m and 7m-1, the surface and end faces of the n-type amorphous film 2m-1, and the n-type single crystal silicon substrate 1 Contact with some surfaces.

  The photoelectric conversion element 100C is manufactured by the steps (a) to (l) shown in FIGS. In this case, in step (c) of FIG. 2, an i-type amorphous film for the i-type amorphous films 61 to 6m is deposited on the n-type single crystal silicon substrate 1 by the plasma CVD method, and then the p-type is formed. A p-type amorphous film 20 for the amorphous films 11 to 1 m is deposited on the i-type amorphous film for the i-type amorphous films 61 to 6 m by plasma CVD. Further, in step (i) of FIG. 3, the i-type amorphous film for the i-type amorphous films 71 to 7m-1 is converted into the n-type single crystal silicon substrate 1 and the p-type amorphous film 11 by the plasma CVD method. 1m and the semiconductor thin films 31 to 3n, and then the n-type amorphous film 60 for the n-type amorphous films 21 to 2m-1 is formed by the plasma CVD method using the i-type amorphous films 71 to 7m- 1 is deposited on the i-type amorphous film. The gas flow rates when depositing the i-type amorphous film for the i-type amorphous films 61 to 6m and the i-type amorphous film for the i-type amorphous films 71 to 7m-1 are the same. Yes, as shown in Table 1.

  The power generation mechanism in the photoelectric conversion element 100C is substantially the same as the power generation mechanism of the photoelectric conversion element 100, and electrons and positive ions diffused toward the p-type amorphous films 11 to 1m and the n-type amorphous films 21 to 2m-1 side. The holes are separated by an internal electric field by the p-type amorphous film 11 to 1 m / i-type amorphous film 61 to 6 m / n-type single crystal silicon substrate 1 (= pin junction), and the holes are i-type amorphous. The electrons reach the electrodes 41 to 4 m through the material films 61 to 6 m and the p-type amorphous films 11 to 1 m, and the electrons are transferred to the i-type amorphous films 71 to 7 m-1 and the n-type amorphous films 21 to 2 m. -1 to reach the electrodes 51-5m-1.

  The electrons that have reached the electrodes 51 to 5m-1 reach the electrodes 41 to 4m via a load connected between the electrodes 41 to 4m and the electrodes 51 to 5m-1, and recombine with the holes.

  As described above, the photoelectric conversion element 100C is configured such that the electrons and holes photoexcited in the n-type single crystal silicon substrate 1 are converted into the back surface of the n-type single crystal silicon substrate 1 (= n-type single crystal silicon on which the passivation film 2 is formed). This is a back contact type photoelectric conversion element taken out from the surface opposite to the surface of the substrate 1.

  In the photoelectric conversion element 100C, the i-type amorphous films 61 to 6m, the p-type amorphous films 11 to 1m, the i-type amorphous films 71 to 7m-1, and the n-type amorphous films 21 to 2m are used. −1, i-type amorphous films 61 to 6m and p-type amorphous films 11 to 1m are i-type amorphous films 71 to 7m-1 and n-type amorphous films 21 to 2m−. Semiconductor thin films 31 to 3 n exist so as not to contact 1. Therefore, the insulation can be improved as described in the photoelectric conversion element 100.

  In the photoelectric conversion element 100C, since the i-type amorphous films 61 to 6m exist between the n-type single crystal silicon substrate 1 and the p-type amorphous films 11 to 1m, the n-type single crystal silicon substrate Recombination of holes at the interface between 1 and the p-type amorphous films 11 to 1 m is suppressed. Furthermore, in the photoelectric conversion element 100C, since the i-type amorphous films 71 to 7m-1 exist between the n-type single crystal silicon substrate 1 and the n-type amorphous films 21 to 2m-1, Recombination of electrons at the interface between the single crystal silicon substrate 1 and the n-type amorphous films 21 to 2m−1 is suppressed.

  As a result, the short-circuit photocurrent increases and the conversion efficiency of the photoelectric conversion element 100C can be improved.

  The other description of the photoelectric conversion element 100C is the same as the description of the photoelectric conversion element 100.

  In the photoelectric conversion elements 100, 100A, 100B, and 100C, the light incident side surface of the n-type single crystal silicon substrate 1 (= the surface on which the passivation film 2 is formed) may have a texture structure. In this case, in the step (a) of FIG. 2, after the n-type single crystal silicon substrate 1 is ultrasonically cleaned with ethanol or the like, the surface of the n-type single crystal silicon substrate 1 is chemically anisotropically etched using alkali. Then, the surface of the n-type single crystal silicon substrate 1 is textured. Thereafter, as described above, the natural oxide film is removed using hydrofluoric acid, and the surface of the n-type single crystal silicon substrate 1 is terminated with hydrogen.

  In the photoelectric conversion elements 100, 100A, 100B, and 100C, the semiconductor thin films 31 to 3n are described as being made of i-type a-SiC. However, in the first embodiment, the semiconductor thin films 31 to 3n are not limited thereto. May be made of any of i-type a-SiO, i-type a-SiN, and i-type a-SiCN. In general, p-type amorphous films 11 to 1m and n-type amorphous films What is necessary is just to consist of a semiconductor material with an optical band gap larger than both 21-2m-1. In this case, the p-type amorphous films 11 to 1m, the n-type amorphous films 21 to 2m-1, and the semiconductor thin films 31 to 3n may all be made of the same material (for example, a-SiC). The thin films 31 to 3n include the semiconductor thin film by containing more C than the amount of carbon (C) in the a-SiC constituting the p-type amorphous films 11 to 1m and the n-type amorphous films 21 to 2m-1. The optical band gaps 31 to 3n are set larger than the optical band gaps of the p-type amorphous films 11 to 1m and the n-type amorphous films 21 to 2m-1. The same applies to the case where all of the p-type amorphous films 11 to 1m, the n-type amorphous films 21 to 2m-1 and the semiconductor thin films 31 to 3n are made of the same material other than a-SiC.

  Furthermore, in the photoelectric conversion elements 100, 100A, 100B, and 100C, the semiconductor thin films 31 to 3n may not have i-type conductivity, and the B concentration contained in the p-type amorphous films 11 to 1m. B may be contained lower than that, and P lower than the P concentration contained in the n-type amorphous films 21 to 2m−1 may be contained. Thus, if the dopant concentration in the semiconductor thin films 31 to 3n is lower than the dopant concentration in the p-type amorphous films 11 to 1m and the n-type amorphous films 21 to 2m-1, the semiconductor thin films 31 to 3n The conductivity is lower than the conductivity of the p-type amorphous films 11 to 1m and the n-type amorphous films 21 to 2m-1, and the carriers (electrons and holes) are p-type amorphous films 11 to 1m. This is because it becomes difficult to flow between the n-type amorphous films 21 to 2m−1.

  Furthermore, in the photoelectric conversion elements 100, 100A, 100B, and 100C, the semiconductor thin films 31 to 3n have an optical band larger than both the p-type amorphous films 11 to 1m and the n-type amorphous films 21 to 2m-1. You may consist of the structure which laminated | stacked the 2 or more types of semiconductor material which has a gap. When the semiconductor thin films 31 to 3n have a structure in which the semiconductor material A and the semiconductor material B are stacked and the optical band gap of the semiconductor material A is larger than the optical band gap of the semiconductor material B, the semiconductor thin films 31 to 3n You may comprise by the laminated structure of material A / semiconductor material B / semiconductor material A. FIG. With such a laminated structure, even if carriers are injected into the semiconductor thin films 31 to 3n, the injected carriers are confined in the semiconductor material B, and the p-type amorphous films 11 to 1m and the n-type This is because it becomes difficult to flow between the amorphous films 21 to 2m−1.

  Further, in the photoelectric conversion elements 100, 100A, 100B, and 100C, it has been described that the p-type amorphous films 11 to 1m are made of p-type a-Si. However, in the first embodiment, the present invention is not limited to this. The type amorphous films 11 to 1m are made of any of p-type a-SiC, p-type a-SiO, p-type a-SiN, p-type a-SiCN, p-type a-SiGe, and p-type a-Ge. It may be.

  Furthermore, in the photoelectric conversion elements 100, 100A, 100B, and 100C, it has been described that the n-type amorphous films 21 to 2m-1 are made of n-type a-Si. However, the first embodiment is not limited thereto. The n-type amorphous films 21 to 2m-1 are made of n-type a-SiC, n-type a-SiO, n-type a-SiN, n-type a-SiCN, n-type a-SiGe, and n-type a-Ge. It may consist of either.

  Further, in the photoelectric conversion elements 100A and 100C, the i-type amorphous films 61 to 6m are described as being made of i-type a-Si. However, in the first embodiment, the i-type amorphous film is not limited thereto. The films 61 to 6m may be made of any of i-type a-SiC, i-type a-SiO, i-type a-SiN, i-type a-SiCN, and i-type a-SiGe.

  Further, in the photoelectric conversion elements 100B and 100C, it has been described that the i-type amorphous films 71 to 7m-1 are made of i-type a-Si. However, in the first embodiment, the i-type non-film is not limited to this. The crystalline films 71 to 7m-1 may be made of any of i-type a-SiC, i-type a-SiO, i-type a-SiN, i-type a-SiCN, and i-type a-SiGe.

  That is, in the photoelectric conversion elements 100, 100A, 100B, and 100C, the p-type amorphous films 11 to 1m, the n-type amorphous films 21 to 2m-1, and the semiconductor thin films 31 to 3n are shown in Table 2, respectively. Any of the materials may be used, and in the photoelectric conversion elements 100A, 100B, and 100C, the i-type amorphous films 61 to 6m and / or the i-type amorphous films 71 to 7m-1 are respectively surfaces. You may consist of either of the materials shown in 2.

In this case, p-type a-SiC is formed by the above-described plasma CVD method using SiH ₄ gas, CH ₄ gas, B ₂ H ₆ gas, and H ₂ gas as material gases. The p-type a-SiO is formed by the above-described plasma CVD method using SiH ₄ gas, oxygen (O ₂ ) gas, B ₂ H ₆ gas and H ₂ gas as material gases. The p-type a-SiN is formed by the above-described plasma CVD method using SiH ₄ gas, NH ₃ gas, B ₂ H ₆ gas and H ₂ gas as material gases. The p-type a-SiCN is formed by the above-described plasma CVD method using SiH ₄ gas, CH ₄ gas, NH ₃ gas, B ₂ H ₆ gas and H ₂ gas as material gases. The p-type a-SiGe is formed by the above-described plasma CVD method using SiH ₄ gas, germane (GeH ₄ ) gas, B ₂ H ₆ gas and H ₂ gas as material gases. The p-type a-Ge is formed by the above-described plasma CVD method using GeH ₄ gas, B ₂ H ₆ gas, and H ₂ gas as material gases.

The n-type a-SiC is formed by the above-described plasma CVD method using SiH ₄ gas, CH ₄ gas, PH ₃ gas, and H ₂ gas as material gases. The n-type a-SiO is formed by the above-described plasma CVD method using SiH ₄ gas, O ₂ gas, PH ₃ gas, and H ₂ gas as material gases. The n-type a-SiN is formed by the above-described plasma CVD method using SiH ₄ gas, NH ₃ gas, PH ₃ gas, and H ₂ gas as material gases. The n-type a-SiCN is formed by the above-described plasma CVD method using SiH ₄ gas, CH ₄ gas, NH ₃ gas, PH ₃ gas, and H ₂ gas as material gases. The n-type a-SiGe is formed by the above-described plasma CVD method using SiH ₄ gas, GeH ₄ gas, PH ₃ gas, and H ₂ gas as material gases. The n-type a-Ge is formed by the above-described plasma CVD method using GeH ₄ gas, PH ₃ gas, and H ₂ gas as material gases.

Furthermore, i-type a-SiC is formed by the above-described plasma CVD method using SiH ₄ gas, CH ₄ gas, and H ₂ gas as material gases. i-type a-SiO is formed by the above-described plasma CVD method using SiH ₄ gas, O ₂ gas, and H ₂ gas as material gases. i-type a-SiN is formed by the above-described plasma CVD method using SiH ₄ gas, NH ₃ gas, and H ₂ gas as material gases. The i-type a-SiCN is formed by the above-described plasma CVD method using SiH ₄ gas, CH ₄ gas, NH ₃ gas, and H ₂ gas as material gases. i-type a-SiGe is formed by the above-described plasma CVD method using SiH ₄ gas, GeH ₄ gas, and H ₂ gas as material gases.

  Note that i-type a-Ge is also assumed as the i-type amorphous films 61 to 6m and 71 to 7m-1, but the i-type a-Ge has an optical band gap larger than that of the n-type single crystal silicon substrate 1. Therefore, when i-type a-Ge is used as the i-type amorphous films 61 to 6m and 71 to 7m-1, it is difficult to improve the open circuit voltage Voc. This is because in the photoelectric conversion elements 100, 100A, 100B, and 100C, the optical band gaps of the i-type amorphous films 61 to 6m and 71 to 7m-1 dominately determine the open circuit voltage Voc.

  Therefore, in the first embodiment, i-type a-SiC, i-type a-SiO, i-type a-SiN, i-type a-SiCN, and i-type a that are larger than the optical band gap of the n-type single crystal silicon substrate 1. -Si, i-type a-SiGe was used as the i-type amorphous films 61-6m and 71-7m-1.

[Embodiment 2]
FIG. 8 is a cross-sectional view showing the configuration of the photoelectric conversion element according to the second embodiment. Referring to FIG. 8, photoelectric conversion element 200 according to the second embodiment includes p-type single crystal silicon substrate 101, passivation film 102, n-type amorphous films 111 to 11m, and p-type amorphous film 121. -12m-1, semiconductor thin films 131-13n, and electrodes 141-14m, 151-15m-1.

  The p-type single crystal silicon substrate 101 has, for example, a (100) plane orientation and a specific resistance of 0.1 to 1.0 Ω · cm. The p-type single crystal silicon substrate 101 has a thickness of 100 to 300 μm, for example, and preferably has a thickness of 100 to 200 μm.

The passivation film 102 is made of, for example, SiO ₂ and is provided in contact with the light incident side surface of the p-type single crystal silicon substrate 101. And the passivation film 102 has a film thickness of 100 nm, for example.

Each of n-type amorphous films 111 to 11m is made of an amorphous phase, and is provided in contact with the surface of p-type single crystal silicon substrate 101 opposite to the light incident side. Each of the n-type amorphous films 111 to 11m is made of, for example, n-type a-Si and has a film thickness of, for example, 10 nm. The n-type amorphous films 111 to 11m are arranged at a desired interval in the in-plane direction of the p-type single crystal silicon substrate 101. Furthermore, the P concentration in each of the n-type amorphous films 111 to 11m is, for example, 5 × 10 ¹⁹ cm ⁻³ .

The p-type amorphous films 121 to 12m−1 are made of an amorphous phase, and are respectively between the n-type amorphous films 111 and 112, between the n-type amorphous films 112 and 113,. Between the type amorphous films 11m-1 and 11m, the semiconductor thin films 131, 132; 133, 134;. Each of the p-type amorphous films 121 to 12m−1 is made of, for example, p-type a-Si, and has a film thickness of, for example, 10 nm. Further, the B concentration in each of the p-type amorphous films 121 to 12m−1 is, for example, 5 × 10 ¹⁹ cm ⁻³ .

  Each of the semiconductor thin films 131 to 13n is made of, for example, i-type a-SiC. Each of the semiconductor thin films 131 to 13n has a film thickness of, for example, several tens of nm or more, and generally has a film thickness that carriers (electrons and holes) cannot tunnel. The semiconductor thin film 131 is disposed in contact with the n-type amorphous film 111, the p-type amorphous film 121, and the p-type single crystal silicon substrate 101, and the semiconductor thin film 132 is formed of the n-type amorphous film 112, p The semiconductor thin film 133 is in contact with the n-type amorphous film 112, the p-type amorphous film 122, and the p-type single crystal silicon substrate 101. The semiconductor thin film 134 is disposed in contact with the n-type amorphous film 113, the p-type amorphous film 122, and the p-type single crystal silicon substrate 101, and the semiconductor thin film 135 is formed of the n-type amorphous film 113. The p-type amorphous film 123 and the p-type single crystal silicon substrate 101 are disposed in contact with each other. Similarly, the semiconductor thin film 13n-1 includes an n-type amorphous film 11m-1 and a p-type amorphous film. Film 12m-1 and p-type single crystal silicon Is disposed in contact with the emission substrate 101, the semiconductor thin film 13n is, n-type amorphous film 11m, are disposed in contact with the p-type amorphous film 12m-1 and p-type single crystal silicon substrate 101.

  The electrodes 141 to 14m are provided in contact with the n-type amorphous films 111 to 11m, respectively. The electrodes 151 to 15m-1 are provided in contact with the p-type amorphous films 121 to 12m-1, respectively. And each of the electrodes 141-14m and 151-15m-1 consists of silver (Ag), for example.

  The n-type amorphous films 111 to 11m and the p-type amorphous films 121 to 12m-1 have the same length in the direction perpendicular to the paper surface of FIG. The area occupation ratio, which is the ratio of the entire area of the n-type amorphous films 111 to 11m to the area of the p-type single crystal silicon substrate 101, is 60 to 93%. The area occupation ratio, which is the ratio of the entire area of 12m−1 to the area of the p-type single crystal silicon substrate 101, is 5 to 20%.

  As described above, the area occupation ratio of the n-type amorphous films 111 to 11m is made larger than the area occupation ratio of the p-type amorphous films 121 to 12m-1 in the p-type single crystal silicon substrate 101. The separated electrons and holes are easily separated by the pn junction (n-type amorphous film 111-11m / p-type single crystal silicon substrate 101), and the contribution rate of photoexcited electrons and holes to power generation is increased. Because.

  The photoelectric conversion element 200 is manufactured according to the steps (a) to (l) shown in FIGS. In this case, the p-type amorphous films 11 to 1m, the n-type amorphous films 21 to 2m-1, the semiconductor thin films 31 to 3n, and the electrodes 41 to 4m and 51 to 5m-1 are respectively connected to the n-type amorphous film 111. To 11m, p-type amorphous films 121 to 12m-1, semiconductor thin films 131 to 13n, and electrodes 141 to 14m, 151 to 15m-1. The n-type amorphous films 111 to 11m have the same material gas as the n-type amorphous films 21 to 2m-1 shown in Table 1 and the same conditions as the conditions of the n-type amorphous films 21 to 2m-1. The p-type amorphous films 121 to 12m-1 are formed of the same material gas as the p-type amorphous films 11 to 1m shown in Table 1 and the p-type amorphous films 11 to 1m. It is formed by a plasma CVD method using the same conditions. The semiconductor thin films 131 to 13n are formed by the plasma CVD method using the same material gas as the semiconductor thin films 31 to 3n shown in Table 1 and the same conditions as the conditions of the semiconductor thin films 31 to 3n.

  In the photoelectric conversion element 200, when sunlight is irradiated to the photoelectric conversion element 200 from the passivation film 102 side, electrons and holes are photoexcited in the p-type single crystal silicon substrate 101.

  Even if the photoexcited electrons and holes diffuse to the passivation film 102 side, they are not easily recombined by the passivation effect of the p-type single crystal silicon substrate 101 by the passivation film 102, and the n-type amorphous films 111 to 11m and p Diffusion to the side of the type amorphous films 121 to 12m-1.

  Then, the electrons and holes diffused toward the n-type amorphous films 111 to 11m and the p-type amorphous films 121 to 12m-1 are transferred to the n-type amorphous films 111 to 11m / p-type single crystal silicon substrate 101. The electrons are separated by an internal electric field due to (= pn junction), the electrons reach the electrodes 141 to 14m through the n-type amorphous films 111 to 11m, and the holes are p-type amorphous films 121 to 12m-1. To reach the electrodes 151-15m-1.

  The electrons that have reached the electrodes 141 to 14m reach the electrodes 151 to 15m-1 via a load connected between the electrodes 141 to 14m and the electrodes 151 to 15m-1, and recombine with the holes.

  As described above, the photoelectric conversion element 200 converts the electrons and holes photoexcited in the p-type single crystal silicon substrate 101 into the back surface of the p-type single crystal silicon substrate 101 (= p-type single crystal silicon on which the passivation film 102 is formed). This is a back-contact photoelectric conversion element that is taken out from the surface opposite to the surface of the substrate 101.

  In the photoelectric conversion element 200, the n-type amorphous films 111 to 11m and the p-type amorphous films 121 to 12m-1 are not in direct contact with each other, and the n-type amorphous films 111 to 11m and the p-type are not in contact with each other. Semiconductor thin films 131 to 13n exist between the amorphous films 121 to 12m-1. Therefore, as described in the photoelectric conversion element 100, the insulating property can be improved.

  FIG. 9 is a cross-sectional view showing a configuration of another photoelectric conversion element according to the second embodiment. The photoelectric conversion element according to Embodiment 2 may be a photoelectric conversion element 200A shown in FIG.

  Referring to FIG. 9, photoelectric conversion element 200 </ b> A is obtained by adding i-type amorphous films 161 to 16 m to photoelectric conversion element 200 shown in FIG. 8, and the rest is the same as photoelectric conversion element 200.

  The i-type amorphous films 161 to 16m are made of an amorphous phase, are in contact with the p-type single crystal silicon substrate 101 and the n-type amorphous films 111 to 11m, respectively, and the p-type single crystal silicon substrate 101 and the n-type It arrange | positions between the amorphous | non-crystalline films 111-11m. Each of the i-type amorphous films 161 to 16m is made of, for example, i-type a-Si, and has a film thickness of, for example, 10 nm. Further, the i-type amorphous films 161 to 16m have the same width as the n-type amorphous films 111 to 11m in the in-plane direction of the p-type single crystal silicon substrate 101 (the left-right direction in the paper surface of FIG. 9), respectively. Have. Furthermore, the i-type amorphous films 161 to 16m have the same length as the n-type amorphous films 111 to 11m, respectively, in the direction perpendicular to the paper surface of FIG.

  In the photoelectric conversion element 200A, the thicknesses of the p-type amorphous films 121 to 12m−1 are the thicknesses of the n-type amorphous films 111 to 11m and the i-type amorphous films 161 to 16m. And the total film thickness.

  In the photoelectric conversion element 200A, the semiconductor thin film 131 includes a part of the surface and end face of the n-type amorphous film 111, the end face of the i-type amorphous film 161, and the surface of the p-type amorphous film 121. The semiconductor thin films 132 and 133 are in contact with a part of the surface and the end face of the n-type amorphous film 112 and the i-type amorphous film 162. The semiconductor thin films 134 and 135 are in contact with the end surfaces of the p-type amorphous films 121 and 122, and a part of the surface of the p-type single crystal silicon substrate 101. Part of the surface and end face, the end face of i-type amorphous film 163, the surfaces and end faces of p-type amorphous films 122 and 123, and the part of the surface of p-type single crystal silicon substrate 101 are in contact with each other. Hereinafter, in the same manner, the semiconductor thin films 13n-2 and 13n-1 include a partial surface and end face of the n-type amorphous film 11m-1, an end face of the i-type amorphous film 16m-1, and a p-type. The semiconductor thin film 13n is in contact with the surfaces and end faces of the amorphous films 12m-2 and 12m-1 and part of the surface of the p-type single crystal silicon substrate 101, and the semiconductor thin film 13n is part of the surface of the n-type amorphous film 11m. And the end face, the end face of the i-type amorphous film 16m, the surface and end face of the p-type amorphous film 12m-1, and the partial surface of the p-type single crystal silicon substrate 101.

  200 A of photoelectric conversion elements are manufactured by the process (a)-process (l) shown in FIGS. In this case, in the step (c) of FIG. 2, an i-type amorphous film for the i-type amorphous films 161 to 16m is deposited on the p-type single crystal silicon substrate 101 by the plasma CVD method. An n-type amorphous film for the amorphous films 111 to 11m is deposited on the i-type amorphous film for the i-type amorphous films 161 to 16m by a plasma CVD method. The gas flow rate when depositing the i-type amorphous films for the i-type amorphous films 161 to 16m is the same as the gas flow rate of the i-type amorphous films 61 to 6m shown in Table 1, and n The gas flow rate when depositing the n-type amorphous film for the n-type amorphous films 111 to 11m is the same as the gas flow rate of the n-type amorphous films 21 to 2m-1 shown in Table 1.

  The power generation mechanism in the photoelectric conversion element 200A is substantially the same as the power generation mechanism of the photoelectric conversion element 200, and electrons and positive ions diffused to the n-type amorphous films 111 to 11m and the p-type amorphous films 121 to 12m-1 side. The holes are separated by an internal electric field by the n-type amorphous film 111-11m / i-type amorphous film 161-16m / p-type single crystal silicon substrate 101 (= pin junction), and the electrons are i-type amorphous. It reaches the electrodes 141 to 14m via the films 161 to 16m and the n-type amorphous films 111 to 11m, and the holes reach the electrodes 151 to 15m-1 via the p-type amorphous films 121 to 12m-1. To reach.

  The electrons that have reached the electrodes 141 to 14m reach the electrodes 151 to 15m-1 via a load connected between the electrodes 141 to 14m and the electrodes 151 to 15m-1, and recombine with the holes.

  As described above, the photoelectric conversion element 200 </ b> A uses the electrons and holes photoexcited in the p-type single crystal silicon substrate 101 to convert the back surface of the p-type single crystal silicon substrate 101 (= p-type single crystal silicon on which the passivation film 102 is formed). This is a back-contact photoelectric conversion element that is taken out from the surface opposite to the surface of the substrate 101.

  In the photoelectric conversion element 200A, the n-type amorphous films 111 to 11m and the i-type amorphous films 161 to 16m and the p-type amorphous films 121 to 12m-1 are n-type amorphous. The semiconductor thin films 131 to 13n exist so that the material films 111 to 11m and the i-type amorphous films 161 to 16m do not contact the p-type amorphous films 121 to 12m-1. Therefore, as described in the photoelectric conversion element 100, the insulating property can be improved.

  In the photoelectric conversion element 200A, since the i-type amorphous films 161 to 16m exist between the p-type single crystal silicon substrate 101 and the n-type amorphous films 111 to 11m, the p-type single crystal silicon substrate Recombination of electrons at the interface between 101 and the n-type amorphous films 111 to 11m is suppressed. As a result, the short-circuit photocurrent increases and the conversion efficiency of the photoelectric conversion element 200A can be improved.

  The other description of the photoelectric conversion element 200A is the same as the description of the photoelectric conversion element 200.

  FIG. 10 is a cross-sectional view illustrating a configuration of still another photoelectric conversion element according to the second embodiment. The photoelectric conversion element according to Embodiment 2 may be a photoelectric conversion element 200B shown in FIG.

  Referring to FIG. 10, photoelectric conversion element 200B is obtained by adding i-type amorphous films 171 to 17m-1 to photoelectric conversion element 200 shown in FIG. is there.

  The i-type amorphous films 171 to 17m-1 are made of an amorphous phase, and are in contact with the p-type single crystal silicon substrate 101 and the p-type amorphous films 121 to 12m-1, respectively. 101 and the p-type amorphous films 121 to 12m-1. Each of the i-type amorphous films 171 to 17m-1 is made of, for example, i-type a-Si, and has a film thickness of, for example, 10 nm. The i-type amorphous films 171 to 17m-1 have the same length as the p-type amorphous films 121 to 12m-1 in the direction perpendicular to the paper surface of FIG.

  In the photoelectric conversion element 200B, each of the n-type amorphous films 111 to 11m has a thickness of the p-type amorphous films 121 to 12m-1 and that of the i-type amorphous films 171 to 17m-1. It consists of the total film thickness with the film thickness.

  In the photoelectric conversion element 200B, the semiconductor thin film 131 includes a part of the surface and end surface of the n-type amorphous film 111, the end surface of the i-type amorphous film 171 and the surface of the p-type amorphous film 121. The semiconductor thin films 132 and 133 are in contact with a part of the surface and the end face of the n-type amorphous film 112 and the i-type amorphous film 171. , 172, the surfaces and end surfaces of the p-type amorphous films 121 and 122, and a part of the surface of the p-type single crystal silicon substrate 101. The semiconductor thin films 134 and 135 are n-type amorphous films. 113 part of the surface and end face, i type amorphous films 172 and 173, p type amorphous films 122 and 123, and part of p type single crystal silicon substrate 101. And touch. Hereinafter, in the same manner, the semiconductor thin films 13n-2 and 13n-1 include a partial surface and end face of the n-type amorphous film 11m-1, and end faces of the i-type amorphous films 17m-2 and 17m-1. The semiconductor thin film 13n is in contact with the surfaces and end faces of the p-type amorphous films 12m-2 and 12m-1 and a part of the surface of the p-type single crystal silicon substrate 101. Part of the surface and end face, the end face of the i-type amorphous film 17m-1, the surface and end face of the p-type amorphous film 12m-1, and the part of the surface of the p-type single crystal silicon substrate 101 Touch.

  The photoelectric conversion element 200B is manufactured by steps (a) to (l) illustrated in FIGS. In this case, in the step (i) of FIG. 3, the i-type amorphous film for the i-type amorphous films 171 to 17m-1 is converted into the p-type single crystal silicon substrate 101, the n-type amorphous film by the plasma CVD method. The p-type amorphous films for the p-type amorphous films 121 to 12m-1 are deposited on the 111 to 11m and the semiconductor thin films 131 to 13n by the plasma CVD method. 1 is deposited on the i-type amorphous film. The gas flow rate when depositing the i-type amorphous film for the i-type amorphous films 171 to 17m-1 is the same as the gas flow rate of the i-type amorphous films 61 to 6m shown in Table 1. The gas flow rate when depositing the p-type amorphous film for the p-type amorphous films 121 to 12m-1 is the same as the gas flow rate of the p-type amorphous films 11 to 1m shown in Table 1.

  The power generation mechanism in the photoelectric conversion element 200B is substantially the same as the power generation mechanism of the photoelectric conversion element 200, and the electrons and positive ions diffused to the n-type amorphous films 111 to 11m and the p-type amorphous films 121 to 12m-1 side. The holes are separated by an internal electric field generated by the n-type amorphous films 111 to 11m / p-type single crystal silicon substrate 101 (= pn junction), and electrons pass through the n-type amorphous films 111 to 11m and the electrodes 141 to 11m. 14m and the holes reach the electrodes 151 to 15m-1 through the i-type amorphous films 171 to 17m-1 and the p-type amorphous films 121 to 12m-1.

  The electrons that have reached the electrodes 141 to 14m-1 reach the electrodes 151 to 15m-1 via a load connected between the electrodes 141 to 14m-1 and the electrodes 151 to 15m-1, and are regenerated with holes. Join.

  As described above, the photoelectric conversion element 200B uses electrons and holes photoexcited in the p-type single crystal silicon substrate 101 to convert the back surface of the p-type single crystal silicon substrate 101 (= p-type single crystal silicon on which the passivation film 102 is formed). This is a back-contact photoelectric conversion element that is taken out from the surface opposite to the surface of the substrate 101.

  In the photoelectric conversion element 200B, the n-type amorphous films 111 to 11m, the i-type amorphous films 171 to 17m-1, and the p-type amorphous films 121 to 12m-1 are n-type. Semiconductor thin films 131 to 13n exist so that the amorphous films 111 to 11m do not contact the i-type amorphous films 171 to 17m-1 and the p-type amorphous films 121 to 12m-1. Therefore, as described in the photoelectric conversion element 100, the insulating property can be improved.

  Moreover, in the photoelectric conversion element 200B, since the i-type amorphous films 171 to 17m-1 exist between the p-type single crystal silicon substrate 101 and the p-type amorphous films 121 to 12m-1, the p-type Recombination of holes at the interface between the single crystal silicon substrate 101 and the p-type amorphous films 121 to 12m−1 is suppressed. As a result, the short-circuit photocurrent increases and the conversion efficiency of the photoelectric conversion element 200B can be improved.

  The other description of the photoelectric conversion element 200B is the same as the description of the photoelectric conversion element 200.

  FIG. 11 is a cross-sectional view illustrating a configuration of still another photoelectric conversion element according to the second embodiment. The photoelectric conversion element according to Embodiment 2 may be a photoelectric conversion element 200C shown in FIG.

  Referring to FIG. 11, photoelectric conversion element 200C is obtained by adding i-type amorphous films 161 to 16m and 171 to 17m-1 to photoelectric conversion element 200 shown in FIG. The same as 200.

  The i-type amorphous films 161 to 16m and 171 to 17m-1 are as described above.

  In the photoelectric conversion element 200C, the semiconductor thin film 131 includes a partial surface and end face of the n-type amorphous film 111, end faces of the i-type amorphous films 161 and 171 and a surface of the p-type amorphous film 121. The semiconductor thin films 132 and 133 are in contact with a part of the surface and the end face of the n-type amorphous film 112 and the i-type amorphous film 162. , 171, 172, the surfaces and end faces of the p-type amorphous films 121, 122, and a part of the surface of the p-type single crystal silicon substrate 101, and the semiconductor thin films 134, 135 are made of n-type amorphous Partial surfaces and end faces of the material film 113, end faces of the i-type amorphous films 163, 172, and 173, surfaces and end faces of the p-type amorphous films 122 and 123, and the p-type single crystal silicon substrate 101 Contact with some surfaces. Hereinafter, in the same manner, the semiconductor thin films 13n-2 and 13n-1 include a partial surface and end face of the n-type amorphous film 11m-1, and the i-type amorphous films 16m-1, 17m-2, and 17m. -1 in contact with the surface of the p-type amorphous films 12m-2 and 12m-1 and the end surface of the p-type single crystal silicon substrate 101, and the semiconductor thin film 13n is made of n-type amorphous. Part of the surface and end face of the material film 11m, the end faces of the i-type amorphous films 16m and 17m-1, the surface and end faces of the p-type amorphous film 12m-1, and the p-type single crystal silicon substrate 101 Contact with some surfaces.

  The photoelectric conversion element 200C is manufactured by the steps (a) to (l) shown in FIGS. In this case, in the step (c) of FIG. 2, an i-type amorphous film for the i-type amorphous films 161 to 16m is deposited on the p-type single crystal silicon substrate 101 by the plasma CVD method. An n-type amorphous film for the amorphous films 111 to 11m is deposited on the i-type amorphous film for the i-type amorphous films 161 to 16m by a plasma CVD method. Further, in step (i) of FIG. 3, the i-type amorphous films for the i-type amorphous films 171 to 17m-1 are formed into a p-type single crystal silicon substrate 101 and an n-type amorphous film 111 by plasma CVD. To 11m and the semiconductor thin films 131 to 13n, and then the p-type amorphous film for the p-type amorphous films 121 to 12m-1 is formed by the plasma CVD method using the i-type amorphous films 171 to 17m-1 It is deposited on the i-type amorphous film. The gas flow rate when depositing the i-type amorphous film for the i-type amorphous films 161 to 16m and the i-type amorphous film for the i-type amorphous films 171 to 17m-1 is: The gas flow rate when depositing the n-type amorphous films 111 to 11m is the same as the gas flow rate when depositing the i-type amorphous films 61 to 6m shown in Table 1. The gas flow rate when depositing the n-type amorphous films 21 to 2m-1 shown in Table 1 is the same as that for depositing the p-type amorphous films for the p-type amorphous films 121 to 12m-1. The gas flow rate at that time is the same as the gas flow rate when the p-type amorphous films 11 to 1m shown in Table 1 are deposited.

  The power generation mechanism in the photoelectric conversion element 200C is substantially the same as the power generation mechanism of the photoelectric conversion element 200, and the electrons and positive ions diffused toward the n-type amorphous films 111 to 11m and the p-type amorphous films 121 to 12m-1 side. The holes are separated by an internal electric field by the n-type amorphous film 111-11m / i-type amorphous film 161-16m / p-type single crystal silicon substrate 101 (= pin junction), and the electrons are i-type amorphous. It reaches the electrodes 141 to 14m through the films 161 to 16m and the n-type amorphous films 111 to 11m, and the holes are formed from the i-type amorphous films 171 to 17m-1 and the p-type amorphous films 121 to 12m. -1 to reach the electrodes 151-15m-1.

  The electrons that have reached the electrodes 141 to 14m reach the electrodes 151 to 15m-1 via a load connected between the electrodes 141 to 14m and the electrodes 151 to 15m-1, and recombine with the holes.

  As described above, the photoelectric conversion element 200 </ b> C uses the back surface of the p-type single crystal silicon substrate 101 (= p-type single crystal silicon on which the passivation film 102 is formed). This is a back-contact photoelectric conversion element that is taken out from the surface opposite to the surface of the substrate 101.

  In the photoelectric conversion element 200C, the i-type amorphous films 161 to 16m, the n-type amorphous films 111 to 11m, the i-type amorphous films 171 to 17m-1, and the p-type amorphous films 121 to 12m are used. −1, i-type amorphous films 161 to 16m and n-type amorphous films 111 to 11m are i-type amorphous films 171 to 17m-1 and p-type amorphous films 121 to 12m−. Semiconductor thin films 131 to 13n exist so as not to contact 1. Therefore, as described in the photoelectric conversion element 100, the insulating property can be improved.

  In the photoelectric conversion element 200C, since the i-type amorphous films 161 to 16m exist between the p-type single crystal silicon substrate 101 and the n-type amorphous films 111 to 11m, the p-type single crystal silicon substrate Recombination of electrons at the interface between 101 and the n-type amorphous films 111 to 11m is suppressed. Furthermore, in the photoelectric conversion element 200C, since the i-type amorphous films 171 to 17m-1 exist between the p-type single crystal silicon substrate 101 and the p-type amorphous films 121 to 12m-1, Recombination of holes at the interface between the single crystal silicon substrate 101 and the p-type amorphous films 121 to 12m−1 is suppressed.

  As a result, the short-circuit photocurrent increases and the conversion efficiency of the photoelectric conversion element 200C can be improved.

  The other description of the photoelectric conversion element 200C is the same as the description of the photoelectric conversion element 200.

  In the photoelectric conversion elements 200, 200A, 200B, and 200C, the surface on the light incident side of the p-type single crystal silicon substrate 101 (= the surface on which the passivation film 102 is formed) may have a texture structure. In this case, after the p-type single crystal silicon substrate 101 is ultrasonically cleaned with ethanol or the like in the step (a) of FIG. 2, the surface of the p-type single crystal silicon substrate 101 is chemically anisotropically etched using alkali. Then, the surface of the p-type single crystal silicon substrate 101 is textured. Thereafter, as described above, the natural oxide film is removed using hydrofluoric acid, and the surface of the p-type single crystal silicon substrate 101 is terminated with hydrogen.

  In the photoelectric conversion elements 200, 200A, 200B, and 200C, the semiconductor thin films 131 to 13n are described as being made of i-type a-SiC. However, in the second embodiment, the semiconductor thin films 131 to 13n are not limited thereto. May consist of any of i-type a-SiO, i-type a-SiN, and i-type a-SiCN, and in general, n-type amorphous films 111 to 11m and p-type amorphous films What is necessary is just to consist of a semiconductor material with an optical band gap larger than both of 121-12m-1. In this case, the n-type amorphous films 111 to 11m, the p-type amorphous films 121 to 12m-1, and the semiconductor thin films 131 to 13n may all be made of the same material (for example, a-SiC). The thin films 131 to 13n include a C that is larger than the amount of carbon (C) in the a-SiC constituting the n-type amorphous films 111 to 11m and the p-type amorphous films 121 to 12m-1, so that the semiconductor thin film The optical band gaps 131 to 13n are set larger than the optical band gaps of the n-type amorphous films 111 to 11m and the p-type amorphous films 121 to 12m-1. The same applies to the case where all of the n-type amorphous films 111 to 11m, the p-type amorphous films 121 to 12m-1, and the semiconductor thin films 131 to 13n are made of the same material other than a-SiC.

  Furthermore, in the photoelectric conversion elements 200, 200A, 200B, and 200C, the semiconductor thin films 131 to 13n may not have the i-type conductivity type, and the P concentration contained in the n-type amorphous films 111 to 11m. P may be lower than that of the P-type amorphous films 121 to 12m-1, and B may be lower than the B concentration included in the p-type amorphous films 121 to 12m-1. Thus, if the dopant concentration in the semiconductor thin films 131 to 13n is lower than the dopant concentration in the n-type amorphous films 111 to 11m and the p-type amorphous films 121 to 12m-1, the semiconductor thin films 131 to 13n The conductivity is lower than the conductivity of the n-type amorphous films 111 to 11m and the p-type amorphous films 121 to 12m-1, and the carriers (electrons and holes) are n-type amorphous films 111 to 11m. This is because it becomes difficult to flow between the p-type amorphous films 121 to 12m−1.

  Further, in the photoelectric conversion elements 200, 200A, 200B, and 200C, the semiconductor thin films 131 to 13n have an optical band larger than both the n-type amorphous films 111 to 11m and the p-type amorphous films 121 to 12m-1. You may consist of the structure which laminated | stacked the 2 or more types of semiconductor material which has a gap. When the semiconductor thin films 131 to 13n have a structure in which the semiconductor material A and the semiconductor material B are laminated, and the optical band gap of the semiconductor material A is larger than the optical band gap of the semiconductor material B, the semiconductor thin films 131 to 13n are replaced with the semiconductor. You may comprise by the laminated structure of material A / semiconductor material B / semiconductor material A. FIG. With such a laminated structure, even if carriers are injected into the semiconductor thin films 131 to 13n, the injected carriers are confined in the semiconductor material B, and the n-type amorphous films 111 to 11m and the p-type are confined. This is because it becomes difficult to flow between the amorphous films 121 to 12m-1.

  Further, in the photoelectric conversion elements 200, 200A, 200B, and 200C, it has been described that the n-type amorphous films 111 to 11m-1 are made of n-type a-Si. However, in the second embodiment, the present invention is not limited to this. The n-type amorphous films 111 to 11m-1 are made of n-type a-SiC, n-type a-SiO, n-type a-SiN, n-type a-SiCN, n-type a-SiGe, and n-type a-Ge. It may consist of either.

  Furthermore, in the photoelectric conversion elements 200, 200A, 200B, and 200C, it has been described that the p-type amorphous films 121 to 12m are made of p-type a-Si. However, in the second embodiment, the present invention is not limited to this. The type amorphous films 121 to 12m are made of any of p-type a-SiC, p-type a-SiO, p-type a-SiN, p-type a-SiCN, p-type a-SiGe, and p-type a-Ge. It may be.

  Further, in the photoelectric conversion elements 200A and 200C, the i-type amorphous films 161 to 16m have been described as being made of i-type a-Si. However, in the second embodiment, the i-type amorphous film is not limited thereto. The films 161 to 16m may be made of any of i-type a-SiC, i-type a-SiO, i-type a-SiN, i-type a-SiCN, and i-type a-SiGe.

  Furthermore, in the photoelectric conversion elements 200B and 200C, the i-type amorphous films 171 to 17m-1 have been described as being made of i-type a-Si. However, in the second embodiment, the i-type non-film is not limited thereto. The crystalline films 171 to 17m-1 may be made of any of i-type a-SiC, i-type a-SiO, i-type a-SiN, i-type a-SiCN, and i-type a-SiGe.

  That is, in the photoelectric conversion elements 200, 200A, 200B, and 200C, the n-type amorphous films 111 to 11m, the p-type amorphous films 121 to 12m-1, and the semiconductor thin films 131 to 13n are shown in Table 2, respectively. In the photoelectric conversion elements 200A, 200B, and 200C, the n-type amorphous films 21 to 2m-1, the p-type amorphous films 11 to 1m, and the semiconductor thin films 31 to 3n may be made of any of the materials. I-type amorphous films 161 to 16m and / or i-type amorphous films 171 to 17m-1 constitute i-type amorphous films 61 to 6m and 71 to 7m-1 shown in Table 2, respectively. It may be made of any of the materials to be used.

  N-type a-SiC, n-type a-SiO, n-type a-SiN, n-type a-SiCN, n-type a-SiGe, n-type a-Ge, p-type a-SiC, p-type a-SiO, p-type a-SiN, p-type a-SiCN, p-type a-SiGe, p-type a-Ge, i-type a-SiC, i-type a-SiO, i-type a-SiN, i-type a-SiCN, and i The type a-SiGe is formed by the plasma CVD method using the material gas described above.

  Note that i-type a-Ge is excluded as a material for the i-type amorphous films 161 to 16m and 171 to 17m-1 because the i-type amorphous films 61 to 6m and 71 to 7m-1 described above are excluded. This is the same as the reason why i-type a-Ge is excluded as a material.

  As described above, in the first embodiment, the p-type amorphous films 11 to 1 m and the n-type amorphous film are formed on the back surface (= the surface opposite to the light incident surface) of the n-type single crystal silicon substrate 1. The photoelectric conversion element 100 having a configuration in which the material films 21 to 2m-1 and the semiconductor thin films 31 to 3n are arranged has been described. In the second embodiment, the n-type amorphous films 111 to 11m and the p-type amorphous film 121 are formed on the back surface (= the surface opposite to the light incident surface) of the p-type single crystal silicon substrate 101. The photoelectric conversion element 200 having a configuration in which ˜12 m−1 and the semiconductor thin films 131 to 13 n are arranged has been described.

  Therefore, the photoelectric conversion element according to the embodiment of the present invention is provided with a single crystal silicon substrate having the first conductivity type and a second surface opposite to the first conductivity type, provided on one surface side of the single crystal silicon substrate. A first amorphous film having the conductivity type and a first crystal film provided on one surface side of the single crystal silicon substrate adjacent to the first amorphous film in the in-plane direction of the single crystal silicon substrate, Provided between the second amorphous film having the conductivity type, the first amorphous film, and the second amorphous film, and larger than both the first and second amorphous films What is necessary is just to provide the semiconductor thin film which has an optical band gap.

  In the first embodiment, the photoelectric conversion element 100A including the i-type amorphous films 61 to 6m disposed between the n-type single crystal silicon substrate 1 and the p-type amorphous films 11 to 1m, n Photoelectric conversion element 100B including i-type amorphous films 71 to 7m-1 disposed between n-type single crystal silicon substrate 1 and n-type amorphous films 21 to 2m-1, and n-type single crystal silicon substrate 1 and p-type amorphous films 11 to 1m, i-type amorphous films 61 to 6m, n-type single crystal silicon substrate 1 and n-type amorphous films 21 to 2m-1 The photoelectric conversion element 100 </ b> C including the i-type amorphous films 71 to 7 m−1 disposed therebetween has been described.

  Furthermore, in the second embodiment, the photoelectric conversion element 200A, p including the i-type amorphous films 161 to 16m disposed between the p-type single crystal silicon substrate 101 and the n-type amorphous films 111 to 11m. Photoelectric conversion element 200B including i-type amorphous films 171 to 17m-1 disposed between p-type single crystal silicon substrate 101 and p-type amorphous films 121 to 12m-1, and p-type single crystal silicon substrate 101 and n-type amorphous films 111 to 11m, i-type amorphous films 161 to 16m, p-type single crystal silicon substrate 101, and p-type amorphous films 121 to 12m-1 The photoelectric conversion element 200 </ b> C including the i-type amorphous films 171 to 17 m−1 disposed therebetween has been described.

  Therefore, the photoelectric conversion element according to the embodiment of the present invention is provided with a single crystal silicon substrate having the first conductivity type and a second surface opposite to the first conductivity type, provided on one surface side of the single crystal silicon substrate. A first amorphous film having the conductivity type and a first crystal film provided on one surface side of the single crystal silicon substrate adjacent to the first amorphous film in the in-plane direction of the single crystal silicon substrate, Provided between the second amorphous film having the conductivity type, the first amorphous film, and the second amorphous film, and larger than both the first and second amorphous films A semiconductor thin film having an optical band gap; and an amorphous film having an i-type conductivity type provided between the single crystal silicon substrate and at least one of the first and second amorphous films. That's fine. When an amorphous film having i-type conductivity is provided between the single crystal silicon substrate and both the first and second amorphous films, the amorphous film having i-type conductivity is used. Is provided between the single crystal silicon substrate and the first amorphous film, and has a third amorphous film having i-type conductivity, the single crystal silicon substrate, and the second amorphous film. And a fourth amorphous film having i-type conductivity.

  Furthermore, the method for manufacturing the photoelectric conversion element according to the embodiment of the present invention is provided between the p-type amorphous films 11-1m and the n-type amorphous films 21-2m-1 (or the n-type amorphous film 111). ˜11 m and the p-type amorphous films 121 to 12 m −1) as long as the semiconductor thin films 31 to 3 n (or the semiconductor thin films 131 to 13 n) are arranged. Therefore, in the method of manufacturing a photoelectric conversion element according to the embodiment of the present invention, the second conductivity type opposite to the first conductivity type is formed on one surface of the semiconductor substrate made of single crystal silicon having the first conductivity type. A first step of depositing a first amorphous film comprising: a second step of forming a semiconductor thin film so as to cover both ends of the first amorphous film in the in-plane direction of the semiconductor substrate; Third step of depositing a semiconductor thin film and a second amorphous film having the first conductivity type on one surface of the semiconductor substrate adjacent to the first amorphous film in the in-plane direction of the semiconductor substrate The semiconductor thin film only needs to have an optical band gap larger than both the first and second amorphous films.

  In the first embodiment, the first conductivity type is n-type, and the second conductivity type is p-type. In the second embodiment, the first conductivity type is p-type, and the second conductivity type is n-type.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a photoelectric conversion element and a manufacturing method thereof.

  1 n-type single crystal silicon substrate, 2,102 passivation film, 11-1m, 20, 121-12m-1 p-type amorphous film, 21-2m-1, 60, 111-11m n-type amorphous film, 30, 50, 70 Resist pattern, 31-3n, 40, 131-13n Semiconductor thin film, 41-4m, 51-5m-1, 141-14m, 151-15m-1 Electrode, 100, 100A, 100B, 100C, 200 , 200A, 200B, 200C, 200C photoelectric conversion element, 61-6m, 71-7m-1, 161-16m, 171-17m-1 i-type amorphous film, 101 p-type single crystal silicon substrate.

Claims (13)

A semiconductor substrate made of single crystal silicon having a first conductivity type;
A first amorphous film provided on one surface side of the semiconductor substrate and having a second conductivity type opposite to the first conductivity type;
A second amorphous film having the first conductivity type, provided on one surface side of the semiconductor substrate adjacent to the first amorphous film in an in-plane direction of the semiconductor substrate;
A semiconductor thin film provided between the first amorphous film and the second amorphous film and having an optical band gap larger than both of the first and second amorphous films. Photoelectric conversion element.   2. The photoelectric conversion element according to claim 1, further comprising a third amorphous film provided between the semiconductor substrate and the first amorphous layer and having an i-type conductivity type.   2. The photoelectric conversion element according to claim 1, further comprising a third amorphous film provided between the semiconductor substrate and the second amorphous layer and having an i-type conductivity type.   The third amorphous film is one of i-type amorphous silicon carbide, i-type amorphous silicon nitride, i-type amorphous silicon carbon nitride, i-type amorphous silicon oxide, i-type amorphous silicon, and i-type amorphous silicon germanium. The photoelectric conversion element according to claim 2, comprising: A third amorphous film provided between the semiconductor substrate and the first amorphous layer and having an i-type conductivity;
The photoelectric conversion element according to claim 1, further comprising a fourth amorphous film that is provided between the semiconductor substrate and the second amorphous layer and has an i-type conductivity type.   Each of the third and fourth amorphous films includes i-type amorphous silicon carbide, i-type amorphous silicon nitride, i-type amorphous silicon carbon nitride, i-type amorphous silicon oxide, i-type amorphous silicon, and i-type amorphous. The photoelectric conversion element according to claim 5, comprising any one of silicon germanium.   7. The semiconductor thin film according to claim 1, wherein the semiconductor thin film is made of any one of i-type amorphous silicon carbide, i-type amorphous silicon nitride, i-type amorphous silicon carbon nitride, and i-type amorphous silicon oxide. The photoelectric conversion element as described in 2. The semiconductor substrate is made of n-type single crystal silicon,
The first amorphous film is a p-type amorphous film,
The photoelectric conversion element according to claim 1, wherein the second amorphous film is an n-type amorphous film. The first amorphous film includes p-type amorphous silicon carbide, p-type amorphous silicon nitride, p-type amorphous silicon carbon nitride, p-type amorphous silicon oxide, p-type amorphous silicon, p-type amorphous silicon germanium, and p-type. Made of either amorphous germanium,
The second amorphous film includes n-type amorphous silicon carbide, n-type amorphous silicon nitride, n-type amorphous silicon carbon nitride, n-type amorphous silicon oxide, n-type amorphous silicon, n-type amorphous silicon germanium, and n-type. The photoelectric conversion element according to claim 8, comprising any one of amorphous germanium. The semiconductor substrate is made of p-type single crystal silicon,
The first amorphous film is an n-type amorphous film,
The photoelectric conversion element according to claim 1, wherein the second amorphous film is a p-type amorphous film. The first amorphous film includes n-type amorphous silicon carbide, n-type amorphous silicon nitride, n-type amorphous silicon carbon nitride, n-type amorphous silicon oxide, n-type amorphous silicon, n-type amorphous silicon germanium, and n-type. Made of either amorphous germanium,
The second amorphous film includes p-type amorphous silicon carbide, p-type amorphous silicon nitride, p-type amorphous silicon carbon nitride, p-type amorphous silicon oxide, p-type amorphous silicon, p-type amorphous silicon germanium, and p-type. The photoelectric conversion element according to claim 10, comprising any of amorphous germanium. A first step of depositing a first amorphous film having a second conductivity type opposite to the first conductivity type on one surface of a semiconductor substrate made of single crystal silicon having a first conductivity type. When,
A second step of forming a semiconductor thin film so as to cover both end portions of the first amorphous film in the in-plane direction of the semiconductor substrate;
Depositing the semiconductor thin film and the second amorphous film having the first conductivity type on one surface of the semiconductor substrate adjacent to the first amorphous film in the in-plane direction of the semiconductor substrate And a third step to
The method for manufacturing a photoelectric conversion element, wherein the semiconductor thin film has an optical band gap larger than both of the first and second amorphous films.   The semiconductor thin film made of any one of i-type amorphous silicon carbide, i-type amorphous silicon nitride, i-type amorphous silicon carbon nitride, and i-type amorphous silicon oxide is formed in the second step. The manufacturing method of the photoelectric conversion element of description.

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