JP3351679B2 - Method for manufacturing polycrystalline silicon thin film laminate and silicon thin film solar cell - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a polycrystalline silicon thin film laminate and a silicon thin film solar cell.

[0002]

2. Description of the Related Art At present, solar cells for converting light into electric power are used in various devices, and there is a demand for an improvement in efficiency. A general solar cell uses amorphous silicon, which has good productivity but does not have sufficient photoelectric conversion efficiency. Therefore, use of polycrystalline silicon has been studied.

A method of manufacturing a polycrystalline silicon thin film laminate which realizes this is disclosed in JP-A-5-109638 and JP-A-4-35021.
And JP-A-5-13662.
For example, in the solid layer growth method described in JP-A-5-109638, an amorphous silicon thin film is formed on the surface of a substrate by a CVD (Chemical Vapor Deposition) method, and this silicon thin film is heated to about 600 (° C.). By annealing at a high temperature for crystallization, a polycrystalline silicon thin film laminate is manufactured.
Further, in the layer-by-layer method and the chemical annealing method described in JP-A-4-35021 and JP-A-5-36062,
By repeatedly depositing an amorphous silicon thin film and exposing with hydrogen plasma in a plasma CVD method, a polycrystalline silicon thin film laminate is manufactured.

[0004]

Although a polycrystalline silicon thin film laminate can be manufactured by the above-described method, a high-quality polycrystalline silicon thin film laminate can be manufactured with good productivity by the above-described method. It is difficult.

In other words, in the solid layer growth method described in Japanese Patent Application Laid-Open No. 5-109638, since annealing is performed at a high temperature of 600 (° C.), heat resistance is required for the substrate, and an inexpensive glass substrate or the like must be used. Can not. In addition, since a long time is required for annealing, the throughput is low.

In this respect, Japanese Patent Application Laid-Open Nos. Hei 4-35021 and Hei 5-
According to the layer-by-layer method and the chemical annealing method described in JP 136062, a polycrystalline silicon thin film laminate can be manufactured at a relatively low throughput at a low temperature, but this method cannot increase the crystal grain size.

In the polycrystalline silicon thin film laminate manufactured by the above-described various methods, silicon is (11)
0) It has been found that the crystal has an orientation, and it has been confirmed that crystal grains grown in this orientation frequently have defects such as twins.

[0008]

According to the first aspect of the present invention ,
An amorphous or microcrystalline silicon thin film is formed on the substrate surface.
The silicon thin film is irradiated with a laser beam (1
11) Seed layer made of oriented polycrystalline silicon crystal grains
Is formed, and the surface of this seed layer is irradiated with an energy beam.
While depositing silicon atoms or silicon compound molecules
To form a (111) oriented polycrystalline silicon growth layer
I did it. Therefore, the (111) oriented polycrystalline silicon
(111) oriented polycrystal on the surface of the seed layer made of copper
Since a silicon growth layer is deposited, the (111) distribution
A polycrystalline silicon thin film with a desired thickness is formed to a desired thickness.
A polycrystalline silicon thin film laminate with few defects is manufactured.
Also, the seed layer and growth layer may be exposed to an oxidizing atmosphere during the manufacturing process.
Polysilicon thin film is (111) oriented because it is not exposed
Grown from (111) oriented polycrystalline silicon.
(111) oriented polycrystalline silicon on the surface of the seed layer
Grow with a large grain size .

The silicon thin film solar cell according to the second aspect of the present invention.
The pond is used for manufacturing the polycrystalline silicon thin film laminate according to claim 1.
The polycrystalline silicon thin film stack produced by the method
As a carrier generation layer. Therefore, the multiple according to claim 1
Multi-layer manufactured by the method for manufacturing a crystalline silicon thin film laminate
Crystalline silicon thin film stack has few defects and large particle size
And a silicon thin film having this as a photocarrier generation layer
Solar cells have high conversion efficiency .

[0010]

[0011]

[0012]

[0013]

[0014]

[0015]

FIG. 1 shows a first embodiment of the present invention.
This will be described below with reference to FIG. First, the polycrystalline silicon thin film laminate 1 of the present embodiment includes a Pyrex substrate 2 and a polycrystalline silicon thin film 3, as shown in FIG. The polycrystalline silicon thin film 3 is laminated on the surface of the substrate 2, and is formed such that most of the crystal planes parallel to the surface of the substrate 2 have the (111) orientation. The orientation ratio is defined based on the X-ray analysis intensity, as shown in the following mathematical formula.

(111) Diffraction intensity ratio = 1 (constant) (220) Diffraction intensity ratio = [Relative intensity of (220) to (111) of sample] / [Relative intensity of (220) to (111) of powder] (311) Diffraction intensity ratio = [relative intensity of (311) to (111) of sample] / [relative intensity of powder (311) to (111)] (400) Diffraction intensity ratio = [(400) of sample (Relative intensity with respect to (111)) / [Relative intensity of (400) of powder with respect to (111)] (111) orientation ratio = (111) diffraction intensity ratio / [(111) diffraction intensity ratio + (220) diffraction intensity ratio + (311) Diffraction intensity ratio +
(400) diffraction intensity ratio] (110) orientation ratio = (220) diffraction intensity ratio / [(111) diffraction intensity ratio + (220) diffraction intensity ratio + (311) diffraction intensity ratio +
(400) Diffraction intensity ratio] In this connection, the term “most” means that the ratio to the whole is 0.
It means 5 or more.

Next, the structure of a manufacturing system 11 for manufacturing the above-described polycrystalline silicon thin film laminate 1 will be described with reference to FIG. This manufacturing system 11 has first and second vacuum chambers 12 and 13, and these vacuum chambers 12 and 13 are connected via a gate valve 14. Inside the vacuum chambers 12 and 13,
A substrate transport mechanism (not shown) is provided by a guide rail or the like, and the substrate 2 is transported by the substrate transport mechanism and held at a predetermined position.

A light transmitting window 15 is formed in the tube wall of the first vacuum chamber 12, and a laser light source 16 made of, for example, an ArF excimer laser is disposed at a position facing the light transmitting window 15. ing.

In the second vacuum chamber 13, a beam generator 17 is provided, and a silicon source 18 and an evaporation source 19 are arranged. The silicon source 18 includes a crucible filled with silicon, and the evaporation source 19 includes
It consists of a crucible filled with boron. The beam generator 17 has an electron gun (not shown) here, and this electron gun emits an electron beam as an energy beam. This electron gun is, for example, a filament, an acceleration electrode,
It has a converging lens and a deflecting lens, and deflects and scans the emitted electron beam.

Next, a method of manufacturing the polycrystalline silicon thin film laminate 1 using the above-described manufacturing system 11 will be described below. First, on the surface of the Pyrex substrate 2,
An amorphous or microcrystalline silicon thin film 4 is formed to a film thickness of 500 (nm) by a thin film technique such as an electron beam evaporation method, an ion plating method, a sputtering method, and a plasma CVD method.
Hereinafter, the film is preferably formed to have a thickness of 10 to 200 (nm). The substrate 2 on which the silicon thin film 4 is formed as described above is set in a substrate transfer mechanism inside the first vacuum chamber 12, and after this setting, the inside of the vacuum chamber 12 is evacuated.

Next, as shown in FIG. 1B, the silicon thin film 4 is irradiated with a laser beam from a laser light source 16,
The seed layer 5 is formed by polycrystallizing silicon. In this case, the energy of the excimer laser is set to 200 to 500 (mJ / c
m ² ), and the number of shots is set to 20 to 200. In this case, the temperature of the substrate 2 is 300 to 500 (° C.), preferably 400 (° C.) or less. As described above, the amorphous or microcrystalline silicon thin film 4 is polycrystallized by laser irradiation in a vacuum to form the seed layer 5.
Is formed by crystal grains of polycrystalline silicon having a (111) orientation.

Next, the inside of the second vacuum chamber 13 is evacuated, and after this, the gate valve 14 is opened and the substrate 2 is transferred from the first vacuum chamber 12 to the second vacuum chamber 13 by the substrate transfer mechanism. I do. After this transfer, the gate valve 14 is closed to reduce the internal pressure of the second vacuum chamber 13 to 1 × 10 to ⁴ (Pa) or less, and the beam generator 17 irradiates the substrate 2 with an electron beam as an energy beam. In this case, the energy of the electron beam depends on the accelerating voltage
00 (V) to 100 (kV), preferably 1.0 (kV) to 30 (kV), and current density of 1.0 (μA / cm ² ) to 1.0 (A / cm ² ), preferably 10 (μA / cm ²⁾ ) To 1.0 (mA / cm ² ). Also in this case, the temperature of the substrate 2 is 300 to 500 (° C.), preferably 400 (° C.).
The following is assumed. At the same time, silicon atoms are generated from the silicon source 18 by, for example, an electron beam evaporation method, and are deposited on the surface of the seed layer 5.

Since the mobility of silicon atoms on the surface of the seed layer 5 is increased by the above-mentioned beam irradiation, FIG.
As shown in FIG. 6, a polycrystalline silicon growth layer 6 having a large grain size and high orientation is formed. This growth layer 6 is formed to have a thickness as required. For example, when the polycrystalline silicon thin film laminate 1 is used for a silicon solar cell, the growth layer 6 has a thickness of 1.0 to 5 mm.
It is formed to a thickness of about 0 (μm).

When the growth layer 6 is deposited on the surface of the seed layer 5 made of (111) polycrystalline silicon in a vacuum as described above, this also grows as (111) oriented polycrystalline silicon. (111) oriented polycrystalline silicon thin film 3 is formed on the surface of the substrate.

That is, in the method of manufacturing the polycrystalline silicon thin film laminate 1 of the present embodiment, the amorphous silicon thin film 4 formed by a general thin film technique is polycrystallized by laser irradiation. The (111) -oriented seed layer 5 having a large grain size can be easily formed. Since the growth layer 6 is deposited on the surface of the seed layer 5, the (111) -oriented polycrystalline silicon thin film 3 having a large crystal grain size can be easily formed.

In this manufacturing method, high-temperature heating is not required, so that inexpensive glass or the like can be used as the substrate 2 and long-time annealing is not required, so that the throughput is good. In addition, since the formation of the seed layer 5 and the deposition of the growth layer 6 are performed in a vacuum, the seed layer 5 and the growth layer 6 are not exposed to an oxidizing atmosphere during the manufacturing process, and the polycrystalline silicon thin film 3 becomes (111). Since it is formed as an orientation, there are few defects.

The result of an experiment for verifying that the polycrystalline silicon thin film 3 formed in the (111) orientation has few defects will be described below with reference to FIG. First, an electrode 21 was mounted on the polycrystalline silicon thin film laminate 1 manufactured by the above-described method, and a Schottky diode 22 was manufactured. However, the substrate 2 was formed of n-type single crystal silicon, and the polycrystalline silicon thin film 3 was formed as p-type by boron doping. In addition, this Schottky diode 2
As a test material to be compared with No. 2, a Schottky diode (not shown) in which a polycrystalline silicon thin film having a similar structure and having a (110) orientation by a layer-by-layer method was also manufactured.

When the diode factor n of these Schottky diodes 22 was determined from the current-voltage characteristics, when the polycrystalline silicon thin film 3 had a (111) orientation, n = 1.2.
When the polycrystalline silicon thin film has a (110) orientation, n =
1.6. Since the crystallinity is considered to be better as the diode factor is closer to “1”, the polycrystalline silicon thin film 3 has fewer crystal defects in the (111) orientation than in the (110) orientation.

The present invention is not limited to the above-described embodiment, but allows various modifications. For example, in the above-described polycrystalline silicon thin film laminate 1, Pyrex is exemplified as the material of the substrate 2, but for example, it may be a heat-resistant plastic such as soda lime glass or polyimide, and may be glass, ceramic, plastic, metal, etc. Is also available.

In the above-described method of manufacturing the polycrystalline silicon thin-film laminate 1, the example in which the seed layer 5 is formed directly on the surface of the substrate 2 is exemplified. It is also possible to improve the crystallinity of the silicon thin film 3. When the seed layer 5 is formed via an appropriate thermal buffer layer, the crystal grain size becomes much larger than the film thickness, so that the polycrystalline silicon thin film 3 having a large crystal grain size can be easily obtained.

Such a thermal buffer layer has no effect if it is too thin, but does not increase its effect if it is too thick.
(μm) or more, preferably 0.3 to 3.0 (μm). As the material, a material having a small thermal diffusivity (= thermal conductivity / density × specific heat) is preferable.
O ₂ , TiO ₂ , SiO ₂ , etc. are appropriate. Such a thermal buffer layer is formed by an electron beam evaporation method, an ion plating method, a plasma CVD method, an MO (Metal Organic) CVD method.
A film can be easily formed by a method, a sol-gel method, a wet coating method, or the like.

In the above-described manufacturing method, the seed layer 5
Although the growth layer 6 is deposited on the surface of the substrate by an electron beam evaporation method, for example, the growth layer 6 may be formed by an ion plating method, a sputtering method, a plasma CVD method, or the like. In these cases, the second vacuum chamber 1
The atmosphere inside 3 is in a state corresponding to each. For example, in the ion plating method or the sputtering method, 1 × 10 to ² to 10 (Pa) of Ar, He, N ₂ , H ₂ ,
Alternatively, a mixed gas of these is used, and in the plasma CVD method, 1 × 10 to ^{2 to} 100 (Pa) of SiH ₄ , Si ₂ H ₆ , SiF ₄ ,
SiH ₂ Cl ₂ or a mixed gas of these and H ₂ . In the case of electron beam evaporation, atmosphere 1 × 10 ~ ³ (Pa)
It is also possible to following H _2.

In the sputtering method, a silicon target is used in place of the silicon source 18, and in the plasma CVD method, a cathode electrode is used in place of the silicon source 18. The energy beam emitted by the beam generator 17 is not limited to an electron beam, but may be an ion beam, a laser beam, an X-ray, or the like. However, since the electron beam has a small charged particle mass, the damage to the thin film layer is small, the growth layer 6 can be deposited with few defects, and the deflection is easy.
Can be uniformly deposited. When the pressure inside the chamber during film formation is high, it is preferable to stabilize the operation by differentially exhausting the inside of the electron gun.

In the above-described manufacturing system 11, the case where the seed layer 5 and the growth layer 6 are individually formed inside the two vacuum chambers 12 and 13 has been described as an example. Can be formed inside the vacuum chamber.

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described below based on First, the silicon solar cell 31 of the present embodiment has a structure similar to that of the above-described polycrystalline silicon thin film laminate 1 as a part thereof, and this part is provided on the surface of the substrate 2 with the heat buffer layer 32 interposed therebetween. Te (11
1) A polycrystalline silicon thin film 3 comprising an oriented seed layer 5 and a growth layer 6 is laminated.

However, the seed layer 5 is formed in a p + type by doping boron at a high concentration.
The growth layer 6 is doped with boron to form a p-type, and functions as a photocarrier generation layer of the silicon solar cell 31. An n-type silicon thin film 33 is laminated on the surface of the polycrystalline silicon thin film 3, and a transparent conductive thin film 34 is laminated on this surface.

Next, a first example of a method for manufacturing the silicon solar cell 31 having the above-described structure will be described below. First,
A thermal buffer layer 32 is formed on the surface of the Pyrex substrate 2
The substrate _{2 on} which the thermal buffer layer 32 has been formed is deposited in the second vacuum chamber 13 of the manufacturing system 11 by forming a film having a thickness of 1.0 (μm) by sputtering or the like using rO ₂ and then 300 (° C.). ). Next, the internal pressure of the vacuum chamber 13 is set to 5.0 × 10 to ⁵ (Pa), silicon vapor is generated from the silicon source 18 by electron beam heating, and boron vapor is generated from the evaporation source 19, and the heat buffer layer 32 is heated.
A p-type amorphous silicon thin film 4 is formed to a thickness of 80 (nm) on the surface of.

Next, after the inside of the first vacuum chamber 12 is evacuated, the gate valve 14 is opened, the substrate 2 is transferred from the second vacuum chamber 13 to the first vacuum chamber 12, and then the gate valve 14 is opened. Close. This substrate 2
Is heated to 400 (° C.), the surface is irradiated with a laser beam at an energy density of 350 (mJ / cm ² ) up to 100 shots, and the silicon thin film 4 is polycrystallized to form a polycrystal of (111) orientation. A silicon seed layer 5 is formed.

Next, the substrate 2 is transferred from the first vacuum chamber 12 to the second vacuum chamber 13 and heated to 400 (° C.) while the electron beam is irradiated at an acceleration voltage of 10 (kV) for 200 hours.
(μA / cm ² ). At this time, silicon vapor is generated from the silicon source 18 by electron beam heating, and boron vapor is generated from the evaporation source 19,
A growth layer 6 is formed on the surface of the seed layer 5 to a thickness of 5.0 (μm). As a result, the (111) -oriented p-type polycrystalline silicon thin film 3 is formed on the surface of the substrate 2, so that the polycrystalline silicon thin film laminate 1 is manufactured. In the case where the growth layer 6 is deposited as described above, the amount of generated boron vapor is smaller than that in the case where the silicon thin film 4 is formed.

Next, the polycrystalline silicon thin-film laminate 1 formed as described above is set inside a vacuum chamber of a parallel plate type plasma CVD apparatus (not shown) at 300 (° C.).
To a vacuum and evacuate the inside of the vacuum chamber to PH ₃
/ SiH ₄ = 0.5 (%) source gas is introduced at a total flow rate of 50 (sccm). After the pressure of the raw material gas is set to 30 (Pa), RF (Radio-Frequency) power is supplied to the cathode of the plasma CVD apparatus, and an n-type silicon thin film 33 is formed on the surface of the polycrystalline silicon thin film 3 to a thickness of 20 (nm). Is formed.

Next, a transparent conductive thin film 34 is coated on the surface of the silicon thin film 33 by ITO (I
The silicon solar cell 31 is completed by forming a film with a thickness of 100 (nm) using n-tin oxide. When the silicon solar cell 31 was actually manufactured as described above and the conversion efficiency was measured, it was confirmed that the efficiency was as high as 10.2 (%) [AM 1.5, 100 (mW / cm ² )].

That is, in the method of manufacturing the silicon solar cell 31 of the present embodiment, the (111) -oriented polycrystalline silicon thin film 3 having a large crystal grain size is easily formed similarly to the polycrystalline silicon thin film laminate 1 described above. However, since this is used as a photocarrier generation layer, a silicon solar cell 31 with good conversion efficiency can be manufactured. When the crystal grain size of the polycrystalline silicon thin film 3 manufactured as described above was measured, it was confirmed that the polycrystalline silicon thin film 3 had a large diameter of about 3.0 (μm).

The present invention is not limited to the above-described embodiment, but allows various modifications. For example, in the silicon solar cell 31 of the above embodiment, the n-type silicon thin film 33 is laminated on the p-type polycrystalline silicon thin film 3, but the p-type and the n-type may be reversed. is there.

In place of the silicon thin film 33, Pt or A
It is also possible to form a Schottky barrier with a metal thin film having a large work function such as u. In this case, the conductive thin film 34 can be omitted. Further, the heat buffer layer 3
Metal thin film of Ag, Cu, Mo, etc. on the surface of No. 2
It is also possible to form a film having a thickness of 00 (nm) and form a back surface reflection layer as a lower layer of the polycrystalline silicon thin film 3.

In the above-described method for manufacturing the silicon solar cell 31, the growth source 6 is formed as a p-type, so that the evaporation source 19 generates boron vapor during the film formation. However, such boron or aluminum can be supplied from an evaporation source using a solid source or a gas source, and can also be supplied from a Knudsen cell or an ion gun. In this case, the gas source is B
_{2 H 6, B (C 2} H 5 O) 3, Al (C 5 H 7 O 2) 3, Al (C 3 H 7
O) ₃ , etc. can be used.

The n-type silicon thin film 33 may be polycrystalline, amorphous, or microcrystalline, and may be formed by any of various general thin-film techniques. n
m). When such a silicon thin film 33 is formed as an n-type, P, As
Is supplied by the above method, or PH ₃ , P (C
₂ H ₅ ) ₃ and AsH ₃ may be supplied as CVD gas sources.

The conductive thin film 34 is also formed by sputtering, electron beam evaporation, ion plating, MO,
Various thin film technologies such as CVD method can be used,
It can be formed to a thickness of about 10 (nm) to 1.0 (μm).

Further, a second example of the method for manufacturing the silicon solar cell 31 will be described below. The description of the same parts as those in the first example of the manufacturing method will be omitted. First, a thermal buffer layer 32 is coated on the surface of a Pyrex substrate 2 by ECR (Ele).
Ctronic Cyclotron Resonanse) A film is formed to a thickness of 2.0 (μm) with SiOx by a plasma CVD method.
Is placed in a parallel plate type plasma CVD apparatus (not shown) and heated to 300 (° C.). After the inside of the vacuum chamber is evacuated, PH ₃ / SiH ₄
= 2.0 (%) at a total flow rate of 50 (sccm), the pressure of the raw material gas is set to 30 (Pa), and then RF power is supplied to the cathode to form an n + type silicon thin film 4 with a film thickness of 100 (%). nm).

The substrate 2 on which the silicon thin film 4 is formed is placed inside the first vacuum chamber 12 of the manufacturing system 11, and the surface is irradiated with a laser beam while the whole is heated to 400 (° C.) ( A seed layer 5 of 111+ oriented n + type polycrystalline silicon is formed. Next, the substrate 2 is transferred from the first vacuum chamber 12 to the second vacuum chamber 13 and heated to 400 (° C.), and the electron beam is irradiated at an acceleration voltage of 10 (kV) to 200 (μA / cm ^2). ). At this time, silicon vapor is generated from the silicon source 18 by electron beam heating, and phosphorus vapor is generated from the evaporation source 19, so that the n-type growth layer 6 has a thickness of 4.0 on the surface of the seed layer 5.
(μm). As a result, the (111) -oriented n-type polycrystalline silicon thin film 3 is formed on the surface of the substrate 2, so that the polycrystalline silicon thin film laminate 1 is manufactured.

Next, the polycrystalline silicon thin film laminate 1 formed as described above is placed inside a parallel plate type plasma CVD apparatus and heated to 300 (° C.), and the inside of the vacuum chamber is evacuated. , A source gas of B ₂ H ₆ / SiH ₄ = 0.1 (%) is introduced at a total flow rate of 50 (sccm). After the pressure of the raw material gas is reduced to 30 (Pa), RF power is supplied to the cathode of the plasma CVD apparatus, and a p-type silicon thin film 33 is formed on the surface of the n-type polycrystalline silicon thin film 3 to a thickness of 20 (nm). Film.

Next, a transparent conductive thin film 34 is formed on the surface of the silicon thin film 33 by sputtering to a thickness of 100 (nm) with ITO, whereby the silicon solar cell 31 is completed. When the silicon solar cell 31 was actually manufactured as described above and the conversion efficiency was measured, it was confirmed that the efficiency was as high as 9.5 (%).

That is, in the method of manufacturing the silicon solar cell 31 of the present embodiment, the (111) -oriented polycrystalline silicon thin film 3 having a large crystal grain size is easily formed similarly to the polycrystalline silicon thin film laminate 1 described above. However, since this is used as a photocarrier generation layer, a silicon solar cell 31 with good conversion efficiency can be manufactured. When the crystal grain size of the polycrystalline silicon thin film 3 manufactured as described above was measured, it was confirmed that the polycrystalline silicon thin film 3 had a large diameter of about 2.0 (μm).

Further, the silicon solar cell 3 as described above
In order to verify the effects of the first and second manufacturing methods, a silicon solar cell was manufactured by a conventional method, and the conversion efficiency was measured. In that case, the heat buffer layer 32 and n
After forming a seed layer 5 of type and exposing it to the outside air, a growth layer 6 of n-type polycrystalline silicon is formed to a thickness of 4.0 (μm) by a layer-by-layer method using microwave plasma.
Was formed. At this time, the substrate 2 is heated to 400 (° C.)
A source gas of H ₃ / SiF ₄ = 0.5 (%) was introduced at a total flow rate of 60 (sccm). One cycle of the film formation of 10 (sec) using the source gas and the processing of 30 (sec) using the H ₂ gas is defined as one cycle.
Repeated until 00 cycles.

Since the (110) -oriented n-type polycrystalline silicon thin film 3 is formed on the surface of the substrate 2, a p-type silicon thin film 33 and a conductive thin film 34 are formed thereon. A solar cell was formed. When the conversion efficiency of the silicon solar cell manufactured in this way was measured, it was 6.5 (%) [A
M1.5, 100 (mW / cm ² )]. Further, when the crystal grain size of the polycrystalline silicon thin film 3 was measured, it was confirmed that the diameter was as small as about 1.0 (μm).

[0055]

According to the first aspect of the present invention , the surface of the substrate
A crystalline or microcrystalline silicon thin film is formed.
A thin film of (111) orientation is irradiated with a laser beam
A seed layer made of crystalline silicon crystal grains is formed.
While irradiating the surface of the seed layer with an energy beam,
Atoms or silicon compound molecules are deposited (11
1) To form an oriented polycrystalline silicon growth layer
Was. Therefore, it is made of (111) oriented polycrystalline silicon.
On the surface of the seed layer, from (111) oriented polycrystalline silicon
(111) oriented polycrystalline silicon
Recon thin film is formed to a desired thickness and has few crystal defects
A polycrystalline silicon thin film laminate can be manufactured. Ma
Also, the seed layer and the growth layer may be exposed to oxidizing atmosphere during the manufacturing process.
Therefore, the polycrystalline silicon thin film has a (111) orientation
As-grown, composed of (111) oriented polycrystalline silicon
On the surface of the seed layer, (111) oriented polycrystalline silicon
It can be grown with a large particle size .

The silicon thin film solar cell according to the second aspect of the present invention.
The pond is used for manufacturing the polycrystalline silicon thin film laminate according to claim 1.
Defects in Polycrystalline Silicon Thin Film Stacks Produced by the Method
Low conversion and high particle size, high conversion efficiency
A membrane solar cell can be obtained .

[0057]

[0058]

[0059]

[0060]

[0061]

[Brief description of the drawings]

FIG. 1 is a process chart showing a method for manufacturing a polycrystalline silicon thin film laminate according to a first embodiment of the present invention.

FIG. 2 is a schematic view showing a system for manufacturing a polycrystalline silicon thin film laminate.

FIG. 3 is a cross-sectional view showing a Schottky diode that includes a polycrystalline silicon thin film stack as a part.

FIG. 4 is a sectional view showing a silicon solar cell.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polycrystalline silicon thin film laminated body 2 Substrate 3 Polycrystalline silicon thin film 4 Silicon thin film 5 Seed layer 6 Growth layer 31 Silicon solar cell

Claims (2)

(57) [Claims] An amorphous or microcrystalline silicon is provided on a surface of a substrate.
A silicon thin film is formed and a laser beam is applied to this silicon thin film.
To irradiate (111) oriented polycrystalline silicon crystal grains
A seed layer is formed on the surface of the seed layer.
Silicon atom or siliconization while irradiating giant beam
(111) oriented polycrystalline silicon by depositing compound molecules
A method for manufacturing a polycrystalline silicon thin film laminate, characterized in that a growth layer is formed . 2. A polycrystalline silicon thin film stack according to claim 1.
Polycrystalline silicon thin film produced by a method for producing a body
Characterized by having a body as a photocarrier generation layer.
Recon thin-film solar cells .