JP3403001B2 - Apparatus and method for manufacturing thin film semiconductor by plasma CVD method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a thin film semiconductor by a plasma CVD method, and more specifically, to produce a thin film semiconductor whose composition is controlled by flowing a plurality of material gases having different decomposition efficiencies into a long discharge space. With regard to the device, in particular, a photovoltaic element such as a solar cell is rolled to roll (Roll).
The present invention relates to a device suitable for mass production by the l to roll method.

[0002]

2. Description of the Related Art In a photovoltaic element, a semiconductor layer which is an important constituent element of the photovoltaic element has a semiconductor junction such as a so-called pn junction or pin junction. When a thin film semiconductor such as a-Si is used, phosphine (PH3), diborane (B2)
A raw material gas containing an element serving as a dopant such as H6) is mixed with silane, which is a main raw material gas, and glow discharge decomposed to obtain a semiconductor film having a desired conductivity type. It is known that the above semiconductor junction can be easily achieved by sequentially forming films. Then, in the case of producing such an a-Si-based photovoltaic element, a method of providing an independent film forming chamber for producing each semiconductor layer and producing each semiconductor layer in each film forming chamber is proposed. ing. In many cases, the p-type semiconductor layer forming the photovoltaic element has a very thin layer thickness of several hundred angstroms from the viewpoint of device characteristics. Therefore, when forming a photovoltaic element, especially a stacked photovoltaic element, only the layer thickness uniformity, film adhesion, dopant doping efficiency, characteristic uniformity, and reproducibility affect the element characteristics. Not only that, but also greatly affects the yield of the device. Therefore, in order to obtain a semiconductor thin film that is uniform both spatially and temporally and with good reproducibility, the discharge stability is further improved over a long time, the reproducibility is improved, and the uniformity is improved. Methods and apparatus are required. Further, in order to improve the throughput of the apparatus and reduce the cost, there is required a forming method and apparatus capable of increasing the deposition rate while maintaining the quality of the semiconductor thin film.

In mass production technology, US Pat.
No. 400,409 discloses a continuous plasma CVD apparatus adopting a roll-to-roll system. According to this device,
In general, a plurality of glow discharge regions, a flexible substrate having a desired width, which is sufficiently long, is arranged along a path in which the substrate sequentially penetrates each glow discharge region, and is required in each glow discharge region. It is said that an element having a semiconductor junction can be continuously manufactured by continuously transporting the substrate in the longitudinal direction while depositing the conductive type semiconductor layer described above. In addition, in the specification, a gas gate is used to prevent the dopant gas used in manufacturing each semiconductor layer from diffusing and mixing into another glow discharge region. Specifically, each of the glow discharge regions,
A means for separating each other by a slit-shaped separation passage and for producing a flow of a scavenging gas such as Ar or H2 in the separation passage is adopted.

[0004]

By the way, in the conventional one in which these thin film semiconductor films are laminated and formed, there are several methods for producing a film having a uniform film quality in a large plasma film formation space over a large area. There is a problem. In particular, S
It is difficult to obtain a uniform one over such a large film formation space under the microcrystal manufacturing conditions that require a high H2 dilution ratio and a high RF power density with respect to the iH4 flow rate. However, there is a need for a means of achieving efficient and uniform over a large area. When multiple types of gas are flowed from the end of this space into a long film formation space and plasma decomposition is performed, the direction of gas flow is
For each gas species, peaks of the amount of decomposition occur in descending order of decomposition efficiency, and a gas depletion region is formed so as to draw a tail toward the downstream of the gas flow (see FIG. 2). As conditions for producing good quality microcrystals, there is a [1] hydrogen treatment region in the gas downstream region (this is important for nucleation prior to crystal formation), and [2] conditions for crystal growth. Then, SiH4
It can be mentioned that a high H2 dilution rate is required at a flow rate ratio of / H2. However, due to such a difference in the decomposition efficiency between SiH4 and H2, the decomposition peak of SiH4 is distributed in the vicinity of the gas blowing, and the crystal production conditions deviate in this region. As a result, the outermost surface of the p-layer produced was made amorphous and it was difficult to obtain desired characteristics. In order to avoid this, countermeasure measures such as covering the deposited portion of the thin film in this region (deposition region where microcrystals are not formed) so as not to be deposited on the belt-shaped member are devised. However, such measures cannot be said to be effective use of gas and plasma, and in order to reduce the manufacturing cost, it is necessary to design the device in accordance with the decomposition efficiency of gas species. Needless to say, it is even more difficult to introduce a dopant gas such as BF3 having a different decomposition efficiency to obtain a uniform film.

Therefore, the present invention not only provides an apparatus for producing a high-quality microcrystal p-layer, but also has excellent characteristics uniformity, few defects, and a photovoltaic element capable of mass production. An object is to provide an apparatus and a method for manufacturing a thin film semiconductor.

[0006]

In order to solve the above-mentioned problems, the present invention is characterized in that an apparatus and a method for manufacturing a thin film semiconductor by a plasma CVD method are configured as follows.

That is, the thin-film semiconductor manufacturing apparatus of the present invention is a thin-film semiconductor manufacturing apparatus for applying a high-frequency power to decompose a material gas by plasma discharge to form a thin-film semiconductor on a strip-shaped member. By forming a threshold electrode on a part of the cathode electrode which is the applying electrode, the total electrode area of the cathode electrode in contact with the plasma is the total surface area of the belt-shaped member and the anode electrode in contact with the plasma at the ground potential. It is characterized in that the density of the threshold electrode is changed stepwise or continuously in the flow direction of the material gas. Further, the thin-film semiconductor manufacturing apparatus of the present invention is characterized in that the slit-shaped electrode is composed of a plurality of fin-shaped or block-shaped members on a plate electrode arranged in parallel with the strip-shaped member. There is. Further, the thin film semiconductor manufacturing apparatus of the present invention,
It is characterized in that the slit-shaped electrode is arranged on the flat plate electrode so that the tip end of the slit-shaped electrode has a uniform height so that the closest distance to the strip-shaped member is constant. . Further, the thin film semiconductor manufacturing apparatus of the present invention,
It is characterized in that the threshold electrodes are arranged such that the number per unit area with respect to the flat plate electrode is changed stepwise or continuously in the flow direction of the material gas. Further, in the thin-film semiconductor manufacturing apparatus of the present invention, the number of the slit-shaped electrodes per unit area with respect to the flat plate electrode is large in the material supply rate-determining region, which is the upstream side in the flow direction of the material gas, and is the downstream side. It is characterized by a decrease in the material depletion region. Further, in the thin-film semiconductor manufacturing apparatus of the present invention, a strip-shaped member is continuously passed through a plurality of connected plasma CVD apparatuses, and a plurality of different thin-film semiconductors are laminated and formed on the strip-shaped member by the plasma CVD method. In thin film semiconductor manufacturing equipment,
A part or all of the plurality of plasma CVD apparatuses is constituted by any one of the above-described thin film semiconductor manufacturing apparatuses of the present invention. Further, in the thin-film semiconductor manufacturing apparatus of the present invention, the strip-shaped member is continuously passed through a plurality of connected plasma CVD apparatuses, and at least one or more n-type strip-shaped members are formed on the strip-shaped member by the plasma CVD method.
Of a thin-film semiconductor for forming a p-type, an i-type, and a p-type thin-film semiconductor layer in this order, at least by the above-described p-type thin-film semiconductor layer manufacturing apparatus according to the present invention. It is characterized by being configured. The main component of the p-type thin film semiconductor layers formed by lamination is Si, or Si and microcrystals.

Further, in the method for producing a thin film semiconductor of the present invention, the strip-shaped member is continuously passed through a plasma CVD apparatus formed by connecting a plurality of the strip-shaped members, and at least one set of n or more n-type members is formed on the strip-shaped member by the plasma CVD method. In a method of manufacturing a thin film semiconductor, in which a p-type thin film semiconductor layer, an i-type semiconductor layer, and a p-type thin film semiconductor layer are stacked in this order, at least one of the above-described thin film semiconductor manufacturing apparatuses of the present invention is used to form the p-type thin film semiconductor layer. A p-type thin-film semiconductor whose main component is Si or Si and microcrystals depending on a material gas selected from a part or all of SiH4, CH4, BF3, and H2. It is characterized by forming a layer. In the thin-film semiconductor manufacturing apparatus of the invention, the p-type thin-film semiconductor layer is 13.56 MHz.
The feature is that it is created by the power supply of the sine wave of. Further, the thin-film semiconductor manufacturing apparatus of the present invention is characterized in that the p-type thin-film semiconductor layer is formed at a temperature of 270 ° C. or lower.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention has the above-mentioned structure of the threshold electrode without impairing the uniformity of the characteristics of the deposited film.
A thin film semiconductor is manufactured, which is generally based on the following principle. In a long plasma deposition space, under high-frequency power density plasma conditions that can sufficiently decompose the material gas,
When a material gas such as SiH4 that is relatively easily decomposed by plasma is flowed, the distribution of the deposited film is divided into two regions in the gas flow direction. These are (A) the "material supply rate controlling region" in the gas upstream region and (B) the "material depletion region" in the gas downstream region. (A) "Material supply rate-determining region" in the gas upstream region In this region, most of the SiH4 gas is decomposed by the energy of plasma, and the distribution of the deposited film has a peak. Here, this peak does not change even if the high frequency power is increased or decreased, and the height of the peak is determined by the supply amount of the material gas. It is said that neutral radicals such as SiH3 and SiH2 mainly contribute to the deposition. (B) "Material depletion region" in the gas downstream region In this region, most of the undecomposed SiH4 as a material has been consumed, and the amount of ions and radicals that contribute to deposition is small. On the other hand, the concentration of H (hydrogen) decomposed and produced from SiH4 tends to be high.

When BF3 is further introduced into such a long plasma film forming space, the B concentration is deposited (including ion implantation) with a peak downstream of the Si peak position. It is considered that this B concentration peak is determined by the BF2 + ion species generated by plasma decomposition of BF3. The deviation of each concentration peak position due to the difference in the gas species in the film formation space hinders the uniformity of the characteristics of the deposited film and has a great influence on the device characteristics of the photovoltaic element and the like. The density of the number of the plurality of fin-shaped or block-shaped threshold electrodes in the present invention has a great influence on the gas decomposition of the plasma generated here.
That is, the higher the density, the higher the plasma intensity,
The positive self-bias potential of the cathode electrode also increases.
This enables positively charged ion species to be deposited or ion-implanted on a strip-shaped member at ground potential, and strips BF2 + and H + ions independently of the neutral radicals SiH3 and SiH2. It becomes possible to introduce on the member. As a result, the uniformity of the composition of the deposited film can be ensured even in a long film forming space. Therefore, in the present invention, the difference in the concentration distribution between B and Si can be narrowed by increasing the density of the number of electrodes of the threshold electrode in this region (A). Also, due to the effect of H + ions, it becomes possible to realize the microcrystal manufacturing conditions even in this region. Further, (B) in the gas downstream region, the electrode density of the plurality of fin-shaped or block-shaped threshold electrodes is made relatively low, so that hydrogen ions are damaged to the semiconductor layer previously deposited on the belt-shaped member. It becomes possible to realize the optimum nucleation condition for microcrystal formation. According to the present invention, a thin film semiconductor having a complicated composition can be produced with high quality and uniformly using one long plasma deposition space by using such a threshold electrode. Next, the specific content of the present invention will be described by showing respective concentration distributions of a deposited film formed on a strip-shaped member that is statically held by plasma decomposition of various gases in a long film forming space. (1) The experimental apparatus is that of an example described later, and a 100-nm amorphous silicon i-layer is previously formed on a belt-shaped member serving as a substrate.
About 0Å is deposited. This belt-shaped member was maintained at a predetermined temperature while being stopped without being conveyed. The other conditions for forming the p-layer were the conditions described in the p-type layer column of Table 1-1. The production time of the p-layer is 5 minutes, and the electrode structure of the p-layer is shown in FIG. 4 (a) (medium density in the entire area), and the conventional threshold electrodes are arranged on the flat plate electrode at equal intervals. The composition analysis in the gas flow direction of the deposited film thus obtained was performed by SIMS.
As a result, Si, B, and H concentration profiles were obtained as shown in FIG. As described above, it can be seen that the B concentration in the film is distributed downstream of the position of the Si peak due to BF3, which has a relatively low decomposition efficiency. When the crystallinity of the thin film semiconductor in the upstream region of the gas flow was observed by RHEED, it was found to be amorphous rather than microcrystalline. (2) Next, the electrode structure of the p layer is shown in FIG. 4 (b) (high density in the upstream region), and other manufacturing conditions are the same as in (1). From this result, it can be seen that by increasing the electrode density of the fin-shaped or block-shaped threshold electrode in the upstream portion of the gas flow, the decomposition of BF3 is promoted and the uniformity of the doping of B into the Si film is enhanced. Further, when the crystallinity of the deposited film in the upstream region of the gas flow was evaluated by RHEED, it was confirmed that it was fine crystal. From this, in this area H
It is considered that the decomposition ratio of 2 and SiH4 and the power density of plasma are changed in the microcrystal manufacturing conditions. (3) Further, the electrode structure of the p-layer is as shown in FIG. 4 (c) (high density in the upstream region, low density in the downstream region), and diluted H2 is replaced with D2 (deuterium) in the p-layer manufacturing conditions. The flow rates were the same. S in the gas downstream region of the deposited film thus obtained
As a result of the IMS analysis, almost no D atom was observed. p
In the layer electrode structure shown in FIG. 4A (medium density in the entire region) and FIG. 4B (high density in the upstream region), some incorporation of such D atoms into the deposited film was confirmed. By comparison, it is considered that the ion bombardment of D atoms on the deposited film is considerably reduced.

Unlike the parallel plate type plasma apparatus of the prior art, the apparatus of the present invention has a drawback that the excitation and decomposition reaction of the material gas is promoted only in a limited part near the cathode electrode. Without being
It is possible to efficiently deposit a thin film on the strip-shaped member with a relatively high deposition rate by promoting the above-mentioned material gas excitation and decomposition reaction on the entire discharge space, rather on the anode electrode side including the strip-shaped member. The semiconductor thin film forming apparatus is characterized by the above. That is, the amount of high-frequency power supplied to the cathode is well adjusted, and the material gas introduced into the discharge space is efficiently excited and decomposed by effectively using the supplied high-frequency power, and a high-quality non-single crystal is also used. It is possible to form a thin film semiconductor on the strip-shaped member uniformly with good reproducibility and at a relatively high deposition rate. In the apparatus of the present invention, the density of a plurality of fin-shaped or block-shaped threshold electrodes is such that the decomposition amount peak position of a gas species having a relatively low decomposition efficiency with respect to the gas flow direction and the decomposition of a gas species having a relatively high decomposition efficiency are generated. It is necessary to appropriately optimize the densities in the film formation space so that the quantity peak positions overlap.

In the device of the present invention, as the material of the cathode electrode, stainless steel and its alloys, aluminum and its alloys, and the like are conceivable. In addition to these, if the material has a conductive property, it is particularly limited to these materials. Does not have to be. The same applies to the anode electrode material.
In the device of the present invention, the surface area of the high-frequency power application cathode electrode installed in the glow discharge space in contact with the discharge is made larger than the surface area of the entire grounded electrode (anode electrode) including the strip-shaped member in the discharge space. In addition, the potential (self-bias) of the cathode electrode at the time of forming a thin film semiconductor by causing a glow discharge is adjusted by adjusting the high frequency power to be applied, so that a positive potential, more preferably +5 V or more is maintained. The apparatus is characterized in that a thin film semiconductor is deposited in this state.

Further, in the present invention, a plurality of the slit-shaped electrodes are installed in the conveyance direction of the strip-shaped member, and the intervals between the slit-shaped electrodes are sufficient to maintain the occurrence of discharge between the adjacent slit-shaped electrodes. By providing the interval, a relatively large positive potential can be generated and maintained in the cathode electrode by self-bias. This is
Unlike a bias applying method using a separately provided direct current (DC) power source, etc., it is possible to suppress the occurrence of abnormal discharge due to sparks, etc. As a result, it is possible to stably generate and maintain discharge, and Since a part of the cathode electrode in which the positive self-bias is generated, that is, the tip end of the threshold electrode is relatively close to the strip-shaped member, a relatively large positive potential generated is generated in the strip-shaped member. It is possible to efficiently and stably apply a bias to the deposited film of (3) through the discharge space. This is because in the parallel plate type cathode electrode structure in which the cathode electrode area is smaller than the anode (ground) electrode area, which is typical of the conventional type, for example, a method of simply shortening the distance between the cathode and the substrate or using a DC power source together This is a self-bias potential, which is obviously different from the method of applying a DC voltage to the cathode, and is the DC bias application effect.

[0014]

EXAMPLES Examples of the apparatus and examples of the present invention will be described below, but the present invention is not limited thereto. (Example of Device) FIG. 1 is a schematic cross-sectional view showing the features inside the discharge vessel of the present invention. In the figure, the cathode electrode 100
2 is an insulating insulator 1 on the ground (anode) electrode 1004.
The conductive strip-shaped member 1000 is supported by a plurality of magnet rollers (not shown) on the cathode electrode so as to be physically insulated from the cathode electrode located below and the lamp heater 1005 located above. It is a structure that moves in the direction indicated by the arrow without touching. The material gas is introduced from the gas introduction pipe 1007, passes between the strip-shaped member and the cathode electrode, and the exhaust port 1006.
Is evacuated by a vacuum pump (not shown). SUS316 was used as the material for the cathode electrode and the anode electrode. The discharge region of the glow discharge generated by the high frequency power is the space between the plurality of grounded slit-shaped electrodes 1003 which is a part of the cathode electrode and the space between the strip-shaped member and the cathode electrode. The area is confined by the conductive strip member. When the discharge vessel having such a structure is used, the ratio of the area of the cathode electrode to the area of the grounded anode electrode including the strip-shaped member is obviously larger than 1. Furthermore, the belt-shaped member 1
It is effective to set the closest distance (L1 in the drawing) between 000 and the fin-shaped or block-shaped slit-shaped electrode 1003 that is a part of the cathode electrode to within 5 cm or less. Furthermore, a plurality of threshold electrodes 1003 are installed.
The distance between them is sufficiently large to maintain the discharge, and the appropriate distance (L3 in the figure) is 3 cm or more and 10c.
It is effective to set it within the range of m or less. Further, in the gas flow upstream region, it is preferable to set the interval L2 so that the density of the threshold electrode is in the range of 2 to 3 times the interval L3 in the downstream region. The shape of the cathode electrode of the present invention is not limited to this, and some other examples are shown. 4 (b), 4 (c), 5 (b), 5
An example of a schematic diagram of the cathode electrode shape is shown in (c). In either case, the cathode electrode material is SUS
316 was used. 4 (a) to 4 (c) show an example of a structure in which a strip-shaped electrode is erected perpendicularly to the flat plate electrode surface at the bottom in a direction perpendicular to the transport direction of the strip-shaped member. Multiple vents 1 to allow gas to pass
This is a structure provided with 10. The vent hole may have a size that allows the material gas to pass therethrough and does not impair the function of the cathode electrode. FIG. 4B shows a structure in which the density of the threshold electrode is arranged in the gas upstream region to be twice that in the other regions. FIG. 4C shows FIG. 4B.
Further, the structure is such that the density of the threshold electrode is arranged in the gas downstream region to be half that in the middle region. Figure 5 (a)
From (c) to (c), there is shown an example of a structure in which the strip-shaped electrode is erected perpendicularly to the flat plate electrode surface of the bottom in a direction parallel to the transport direction of the strip-shaped member. The structure is such that a material gas can pass between the end-shaped electrodes at both ends. FIG. 5 (b) shows a structure in which the density of the threshold electrode is arranged in the gas upstream region to be twice that of the other castles. FIG. 5 (c) is the same as FIG. 5 (b).
This structure is arranged so that the density of the threshold electrode in the gas downstream region is half that in the middle region. In these examples, a rectangular type having straight sides is shown, but a shape having curved sides may be used although not shown. The point is that the surface area of the cathode electrode is larger than the surface area of the anode electrode and the structure does not hinder the gas flow. By manufacturing a photovoltaic element using the above-described manufacturing apparatus of the present invention, the above-mentioned problems are solved and the above-mentioned requirements are satisfied, and high quality and excellent on a continuously moving strip-shaped member. It is possible to fabricate a photovoltaic element having excellent uniformity and few defects.

(Photovoltaic Element) FIG. 7 is a schematic view showing the structure of the photovoltaic element manufactured according to the present invention. The example shown in the figure is a single-type photovoltaic element, and is a strip-shaped member 40.
01 (104), lower electrode 4003, first n-type layer 40
04, the first i-type layer 4005, the first p-type layer 4006,
Second n-type layer 4007, second i-type layer 4008, second p-type layer 4009, upper electrode 4010, current collecting electrode 4011.
It consists of The example shown in FIG. 8 is a so-called triple type photovoltaic device, which is configured by stacking three photovoltaic devices using three types of semiconductor layers having different band gaps and / or layer thicknesses as i-type layers. Yes, belt-shaped member 5001
(104), lower electrode 5003, first n-type layer 500
4, first i-type layer 5005, first p-type layer 5006, second n-type layer 5007, second i-type layer 5008, second p-type
Mold layer 5009, third n-type layer 5010, third i-type layer 5
011, a third p-type layer 5012, an upper electrode 5013, and a collector electrode 5014. The configurations of these photovoltaic elements will be described below.

(P-Type Layer) As a material used for the p-type layer in the photovoltaic element of the present invention, a non-single-crystal semiconductor composed of one or more atoms of Group V of the periodic table is suitable. Furthermore, the conductive layer on the light irradiation side is most preferably a microcrystallized semiconductor. The particle size of the fine crystals is preferably 3n
m to 20 nm, and optimally 3 to 10 nm. The additives contained in the p-type layer are listed in Table V of the Periodic Table.
Group elements are suitable, and among them, boron (B), aluminum (Al), and gallium (Ga) are most suitable. Furthermore, in order to further reduce the light absorption in the conductive layer on the light irradiation side, it is preferable to use a semiconductor layer having a band gap larger than that of the semiconductor forming the i-type layer. For example, when the i-type layer is amorphous silicon, it is also possible to use non-single-crystal silicon carbide for the conductive type layer on the light irradiation side.

As described above, when the apparatus of the present invention is used, that is, when a plurality of material gases having different decomposition efficiencies are introduced into a long plasma film forming space and a deposited film is formed by plasma decomposition, [1] The total area of the cathode electrode of the plasma CVD apparatus is larger than the total surface area of the strip-shaped member for forming a deposited film and the anode electrode at the ground potential, and as a result, the cathode when glow discharge occurs An electrode structure in which the potential of the electrode (self-bias) is a positive potential relative to the potential of the strip electrode and the anode electrode at the ground potential. And [2] a "plate electrode" in which the cathode electrode is arranged in parallel with the strip-shaped member, and a plurality of fin-shaped or block-shaped "cut-off electrodes" arranged on the plate electrode that do not hinder the flow of the material gas. The structure must be a combination of "shaped electrodes". and,
[3] In the distribution of the deposited film in the plasma space, the cathodes corresponding to the respective regions in the “material supply rate-determining region” and the “material depletion region” that are formed in this order in the flow direction of the material gas. In the region of the cathode electrode corresponding to the "material supply rate-determining region", the number of electrodes per unit area of the "crimp electrode" of the electrode is increased, and in the region of the cathode electrode corresponding to the "material depletion region". The structure should be reduced and placed on each "plate electrode". With such a cathode electrode structure, the film deposited on the belt-shaped member can be a highly composition-controlled thin film semiconductor. In particular, it is also effective in realizing a good-quality p-type microcrystalline silicon thin film in a photovoltaic device, improving discharge stability, improving reproducibility, improving uniformity, and reproducing over a long period of time. It is possible to realize a high-quality semiconductor device with good performance. Furthermore, by using the device of the present invention, it is possible to realize an extremely good pn junction interface, especially in a stacked photovoltaic element. Using the plasma CVD apparatus of the present invention described above,
By producing a photovoltaic element, it is possible to solve the above-mentioned problems and to produce a photovoltaic element having high quality and excellent uniformity by carrying a continuously moving strip-shaped member. In Examples 10 and below, a photovoltaic device was formed by using the thin film semiconductor and photovoltaic device manufacturing apparatus according to the present invention, and various characteristics of the obtained photovoltaic device were evaluated.

[Embodiment 1] In this embodiment, the continuous plasma CVD apparatus adopting the roll-to-roll system shown in FIG. 6 is used, and the single cell type photovoltaic shown in FIG. 7 is used. A device was produced. At that time, p
The shape of the cathode electrode of the vacuum container for forming the mold layer is shown in FIG.
The shape shown in (b) is used. As the n-type layer forming container and the i-type layer forming container, a forming container having a parallel plate type RF electrode was used. The manufacturing apparatus of FIG. 6 includes vacuum containers 301 and 302 for feeding and winding the belt-shaped member 101, an n-type layer forming vacuum container 601, an i-type layer forming vacuum container 100, and a p-type layer forming vacuum container 602. It is configured to be connected via a gas gate. Each structure of the cathode electrode 603 in the vacuum container 601 and the cathode electrode 604 in the vacuum container 602 was the above-mentioned cathode electrode structure. Using the manufacturing apparatus shown in FIG. 6, under the manufacturing conditions shown in Table 1, an n-type layer, an i-type layer, and a p-type layer were continuously formed by the manufacturing procedure as shown below, and a single film was formed. Photovoltaic device (referred to as Device-Exemplary 1) was produced. (1) First, a vacuum container 301 having a substrate delivery mechanism
The bobbin 303 around which the belt-shaped member 101 was wound was set in the. The strip-shaped member 101 is sufficiently degreased and washed, and a silver thin film having a thickness of 100 nm and a ZnO thin film having a thickness of 1 μm are deposited as a lower electrode by a sputtering method.
Band-shaped member made of US430BA (width 120 mm x length 20
0 m × thickness 0.13 mm) was used. (2) The belt-shaped member 101 was passed through the gas gate and each vacuum container to the vacuum container 302 having the belt-shaped member winding mechanism, and the tension was adjusted so that there was no slack. (3) Each vacuum container 301, 601, 100, 602, 3
02 was evacuated by a vacuum pump (not shown). (4) Each gas gate has a gate gas introduction pipe 131n, 1n
H2 as a gate gas was made to flow at 700 sccm from 31, 132, 131p, and lamp heaters 124n, 12
The belt-shaped member 101 is
Heated to ℃, 350 ℃, 250 ℃. (5) 40 sc of SiH4 gas from the gas introduction pipe 605
cm, PH3 gas (2% H2 diluted product) 50 sccm, H
2 gas at 200 sccm, gas introduction pipes 104a, 104
From b and 104c, SiH4 gas of 100 sccm each,
H2 gas is 500 sccm each from the gas introduction pipe 606,
SiH4 gas was introduced at 10 sccm, BF3 gas (2% H2 diluted product) was introduced at 100 sccm, and H2 gas was introduced at 700 sccm. (6) The pressure inside the vacuum container 301 is 1.
The conductance valve 307 was adjusted so as to be 0 Torr. The pressure inside the vacuum container 601 was adjusted by a conductance valve (not shown) so that the pressure was 1.5 Torr with a pressure gauge (not shown). The pressure inside the vacuum container 100 was adjusted with a conductance valve (not shown) so that the pressure was 1.8 Torr with a pressure gauge (not shown). The pressure inside the vacuum container 602 was adjusted by a conductance valve (not shown) so that the pressure was 1.6 Torr with a pressure gauge (not shown). Vacuum container 302
The internal pressure was adjusted by the conductance valve 308 so as to be 1.0 Torr with the pressure gauge 315. (7) After the pressure adjustment shown in step (6), RF power of 500 W is applied to the cathode electrode 603.
RF power of 200 W for the cathode electrode 4 and 4 for the cathode electrode 604.
RF power of 00 W was introduced in each case. (8) The belt-shaped member 101 is conveyed in the direction of the mark in the figure,
An n-type layer, an i-type layer and a p-type layer were sequentially formed on the belt-shaped member. (9) ITO (In ₂ O ₃ + SnO ₂ ) was formed as a transparent electrode on the p-type layer prepared in the step (8) by vacuum evaporation.
After 0 nm was vapor-deposited, Al was further vapor-deposited by vacuum vapor-depositing to a thickness of 2 μm as a collector electrode to complete the production of the photovoltaic element (element-actual 1). Table 1-1 shows the production conditions of the photovoltaic element according to the present example.

[0019]

[Table 1-1] (Comparative Example 1) This example is different from Example 1 in that the cathode electrode of the vacuum container for forming the p-type layer has a fin type structure and the cathode electrode structure shown in FIG.
In this cathode electrode structure, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode was 2.8 times. This ratio is slightly lower than 2.9 times that in Example 1, but it can be considered that there is no change in the self-bias value and no significant change in the plasma itself. However, the manufacturing conditions of the photovoltaic element were the same as those in Example 1 (Table 1-
1). A single cell type photovoltaic element (element-ratio 1) was produced in the same manner as in Example 1 except for the above points.
In the following, with respect to the photovoltaic elements manufactured in Example 1 and Comparative Example 1, that is, (element-actual 1) and (element-ratio 1), characteristic uniformity, defect density and photodegradation were evaluated. The results will be described. The property uniformity means that the photovoltaic elements on the belt-shaped member manufactured in Example 1 and Comparative Example 1, that is, (element-actual 1) and (element-ratio 1) are 5c at intervals of 10 m.
Cut out in an area of m square, AM-1.5 (100 mW / cm
² ) This is the result of measuring the photoelectric conversion efficiency by installing it under light irradiation and evaluating the variation in the photoelectric conversion efficiency. Comparative Example 1
1.0 for the variation of photovoltaic elements (element-ratio 1)
A variation of the photovoltaic element of Example 1 (Element-Execution 1) is shown as 0. Moreover, the value of (element-actual 1) was shown by making (element-ratio 1) into reference 1.00 about each open circuit voltage. The defect density refers to a photovoltaic element on a belt-shaped member manufactured in Example 1 and Comparative Example 1, that is, 5 cm in a central portion 5 m of (element-actual 1) and (element-ratio 1).
This is the result of evaluating the defect density by cutting out 100 corner areas and measuring the reverse current to detect the presence or absence of defects in each photovoltaic element. Using the defect density of the photovoltaic element (element-ratio 1) of Comparative Example 1 as a reference of 1.00, Example 1
The defect density of the photovoltaic element (element-Execution 1) of No. 1 was shown. The photo-degradation characteristic means that the photovoltaic element on the strip-shaped member manufactured in Example 1 and Comparative Example 1, that is, (element-actual 1) and (element-ratio 1), is 5 cm square in the central portion 5 m. Area of 10
It is the result of evaluating the reduction rate of the photoelectric conversion efficiency by cutting out 0 pieces, setting it under AM-1.5 (100 mW / cm ² ) light irradiation, leaving it for 10,000 hours, measuring the photoelectric conversion efficiency. The reduction rate of the photovoltaic element of Example 1 (element-actual 1) was shown with the reduction rate of the photovoltaic element of Comparative Example 1 (element-ratio 1) as the reference. Table 1-2 shows the above-mentioned variation in photoelectric conversion efficiency, defect density, and photovoltaic element produced in Example 1 and Comparative Example 1, that is, (element-actual 1) and (element-ratio 1). And the photodegradation rate. From Table 1-2, with respect to the photovoltaic element of Comparative Example 1 (element-ratio 1), the photovoltaic element of Example 1 (element-exact 1)
Is excellent in conversion efficiency variation, defect density, photodegradation rate, open circuit voltage, and it was found that the photovoltaic element formed by the manufacturing method of the present invention has excellent characteristics.

[0020]

[Table 1-2] [Example 2] This example is different from Example 1 in that the cathode electrode of the vacuum container for forming the P-type layer has the partition plate shape shown in Fig. 4C. In this cathode electrode structure, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode was 2.9 times. The manufacturing conditions of the photovoltaic element are shown in Table 1-1. As the n-type layer forming container and the i-type layer forming container, a forming container having a parallel plate type RF electrode was used. A single photovoltaic element (element-actual 2) was produced in the same manner as in Example 1 except for the above points. For the photovoltaic elements produced in Example 2 and Comparative Example 1, that is, (Element-Execution 2) and (Element-Ratio 1), the property uniformity was the same as in Example 1.
The defect density, photodegradation and open circuit voltage were evaluated. The results are shown in Table 2-1. From Table 2-1, in comparison with the photovoltaic element of Comparative Example 1 (element-ratio 1), the photovoltaic element of Example 2 (element-actual 2) has variations in conversion efficiency, defect density, and It was found that both the photodegradation rate and the open circuit voltage were excellent.

[0021]

[Table 2-1] [Embodiment 3] This embodiment differs from Embodiment 1 in that the cathode electrode of the vacuum container for forming the p-type layer has the shape of a slit shown in FIG. 5 (b). With this cathode electrode structure,
The ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode was 2.9 times. Also,
The manufacturing conditions of the photovoltaic element are shown in Table 3-1. As the n-type layer forming container and the i-type layer forming container, a forming container having a parallel plate type RF electrode was used. The other points are the same as in Example 1, and the single type photovoltaic element (element-actual 3
Called).

[0022]

[Table 3-1] (Comparative Example 2) This example is different from Example 1 in that the cathode electrode of the vacuum container for forming the p-type layer has a slit-shaped structure and the cathode electrode structure shown in FIG.
In this cathode electrode structure, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode was 2.8 times. This ratio is slightly lower than 2.9 times that in Example 1, but it can be considered that there is no change in the self-bias value and no significant change in the plasma itself. However, the manufacturing conditions of the photovoltaic element were the same as those of Example 3 (Table 3-
1). A single cell type photovoltaic element (element-ratio 2) was prepared in the same manner as in Example 3 except for the above points.
Example 1 is compared with the photovoltaic elements produced in Example 3 and Comparative Example 2, that is, (Element-Execution 3) and (Element-Ratio 2).
In the same manner as the above, the uniformity of characteristics, the defect density, the photodegradation rate, and the open circuit voltage were evaluated. The results are shown in Table 3-2.
From Table 3-2, the photovoltaic element of Comparative Example 2 (element-ratio 2)
On the other hand, the photovoltaic element of Example 3 (element-actual 3) is
It was found that variations in conversion efficiency, defect density, photodegradation rate, and open circuit voltage were all excellent.

[0023]

[Table 3-2] [Embodiment 4] This embodiment differs from Embodiment 3 in that the cathode electrode of the vacuum container for forming the p-type layer has the shape of a slit shown in FIG. 5 (c). With this cathode electrode structure,
The ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode was 2.9 times. Also,
The manufacturing conditions of the photovoltaic element are shown in Table 3-1. As the first conductive type layer forming container and the second conductive type layer forming container, forming containers having parallel plate type RF electrodes were used. A single type photovoltaic element (element-actual 4) was produced in the same manner as in Example 1 except for the above points. With respect to the photovoltaic devices manufactured in Example 4 and Comparative Example 2, that is, (Device-Execution 4) and (Device-Ratio 2), the property uniformity, the defect density and the photodegradation rate were the same as in Example 3. The open circuit voltage was evaluated. The results are shown in Table 4. From Table 4, in comparison with the photovoltaic element of Comparative Example 2 (element-ratio 2), the photovoltaic element of Example 4 (element-actual 4) has variations in conversion efficiency,
It was found that the defect density, the photodegradation rate, and the open circuit voltage were all excellent.

[0024]

[Table 4] [Embodiment 5] In this embodiment, a continuous plasma CVD apparatus adopting the roll-to-roll system shown in FIG. A triple cell type photovoltaic device was prepared. At that time, the shape of the cathode electrode of the vacuum container for producing each p-type layer was the partition plate shape shown in FIG. 4 (b). In this cathode electrode structure, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode is 2.9 times. The n-type layer forming container and the i-type layer forming container are parallel plate type RF.
A forming container with electrodes was used. In the manufacturing apparatus of FIG. 6, although not shown, a vacuum container 601 for n-type layer production,
An apparatus having a structure in which the i-type layer forming vacuum container 100 and the p-type layer forming vacuum container 602 are connected via a gas gate as one set, and two more sets are added, and a total of three sets are repeatedly arranged in series. Was used. Moreover, among them, all the p-type layer forming containers were provided with the above-mentioned formation container having a striped shape, and a triple type photovoltaic element was manufactured. Using such a device (not shown), under the manufacturing conditions shown in Table 5, the first n-type layer, the first i-type layer, and
Second p-type layer, second n-type layer, second i-type layer, second p-type layer
Layer, the third n-type layer, the third i-type layer, and the third p-type layer are sequentially stacked and deposited, and the triple photovoltaic element (element-actual 5) was continuously prepared. Table 5-1 shows the fabrication conditions of the photovoltaic element according to this example.

[0025]

[Table 5-1] (Comparative Example 3) This example differs from Example 5 in that the shape of the cathode electrode of the vacuum container for forming each p-type layer is the cathode electrode structure shown in FIG. 4 (a). In this cathode electrode structure, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode is 2.8 times. However, the manufacturing conditions of the photovoltaic element were the same as those in Example 5 (Table 5-1). The other points are the same as in Example 5, and the triple cell type photovoltaic element (element-ratio 3) is used.
Was produced. With respect to the photovoltaic elements produced in Example 5 and Comparative Example 3, that is, (Element-Executive 5) and (Element-Ratio 3), the characteristic uniformity, the defect density, and the photodegradation rate were the same as in Example 1. The open circuit voltage was evaluated. The results are shown in Table 5-
Shown in 2.

From Table 5-2, in comparison with the photovoltaic element of Comparative Example 3 (element-ratio 3), the photovoltaic element of Example 5 (element-actual 5) has variations in conversion efficiency and defect density. ,as well as,
It has been found that the photo-deterioration rate and the open circuit voltage are both excellent, and a triple photovoltaic element having excellent characteristics can be obtained by the manufacturing method of the present invention.

[0027]

[Table 5-2]

[0028]

According to the present invention, by forming a threshold electrode on a part of the above cathode electrode, the total electrode area of the cathode electrode in contact with plasma is at the ground potential in contact with plasma. It is configured to be larger than the total surface area of the strip-shaped member and the anode electrode, and the density of the threshold electrode is stepwise or continuously changed in the direction of the flow of the material gas.
To provide a manufacturing apparatus and manufacturing method of a thin film semiconductor such as a photovoltaic element, which has high quality and excellent uniformity over a large area, has few defects, and can be mass-produced with high throughput and high reproducibility. be able to.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a thin-film semiconductor manufacturing apparatus using a cathode electrode according to the present invention, which is a conceptual schematic diagram used for explaining an example of a discharge space in the manufacturing apparatus. is there.

FIG. 2 is a composition profile of a deposited film obtained by a conventional cathode electrode forming apparatus.

FIG. 3 is a composition profile of a deposited film obtained by a cathode electrode film forming apparatus according to the present invention.

FIG. 4 is a schematic diagram showing an example of a cathode electrode of the present invention.

FIG. 5 is a schematic view showing an example of a cathode electrode of the present invention.

FIG. 6 is a schematic cross-sectional view of a photovoltaic device manufacturing apparatus using the thin film semiconductor manufacturing apparatus according to the present invention.

FIG. 7 is a conceptual cross-sectional view of a single cell type photovoltaic device according to the present invention.

FIG. 8 is a conceptual cross-sectional view of a triple cell type photovoltaic device according to the present invention.

[Explanation of symbols]

100: Vacuum container 101: Band-shaped members 103a, 103b, 103c: Heater heaters 104a, 104b, 104c: Gas introduction tube 107: Cathode electrodes 124n, 124, 124p: Lamp heaters 129n, 129, 129p, 130: Gas gates 131n, 131 , 131p, 132: Gas gate introduction pipes 301, 302: Vacuum containers 303, 304: Bobbins 305, 306: Idling rollers 307, 308: Conductance valves 310, 311: Exhaust pipes 314, 315: Pressure gauge 513: Exhaust pipes 601, 602 : Vacuum containers 603, 604: Cathode electrodes 605, 606: Gas introduction pipes 607, 608: Exhaust pipe 1000: Conductive strip member 1001: Vacuum container 1002: Cathode electrode 1003: Edged electrode 1004: Anode electrode 1005: Pump heater 1006: Exhaust port 1007: Gas inlet pipe 1008: Gas gate 1009: Insulation insulator 1010: High frequency oscillator 4001: SUS substrate 4002: Ag thin film 4003: ZnO thin film 4004: n-type layer 4005: i-type layer 4006: p-type layer 4007 : ITO 4008: Current collecting electrode 5001: SUS substrate 5002: Ag thin film 5003: ZnO thin film 5004: First n-type layer 5005: First i-type layer 5006: First p-type layer 5007: Second n-type Layer 5008: Second i-type layer 5009: Second p-type layer 5010: Third n-type layer 5011: Third i-type layer 5012: Third p-type layer 5013: ITO 5014: Current collecting electrode

Front page continuation (72) Inventor Yuzo Koda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Takahiro Yajima 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tadashi Sawayama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masahiro Kanai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference References JP-A 1-227428 (JP, A) JP-A 9-64389 (JP, A) JP-A 7-316824 (JP, A) JP-A 1-227426 (JP, A) JP-A 62- 282434 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/205 C23C 16/50

Claims (11)

(57) [Claims] 1. A thin-film semiconductor manufacturing apparatus for applying a high-frequency power to decompose a material gas by plasma discharge to form a thin-film semiconductor on a band-shaped member. By forming a threshold electrode, the sum of the electrode areas of the cathode electrode in contact with the plasma is configured to be larger than the sum of the surface areas of the strip-shaped member and the anode electrode in contact with the plasma at the ground potential, and An apparatus for manufacturing a thin film semiconductor, characterized in that the density of the threshold electrode is changed stepwise or continuously in the flow direction of the material gas. 2. The strip-shaped electrode is constituted by a plurality of fin-shaped or block-shaped members on a flat plate electrode arranged in parallel with the strip-shaped member. Thin-film semiconductor manufacturing equipment. 3. The plate-shaped electrode is arranged on the flat plate electrode so that the tip end of the plate-shaped electrode has a uniform height so that the closest distance to the strip-shaped member is constant. The thin-film semiconductor manufacturing apparatus according to claim 2. 4. The threshold electrodes are arranged such that the number per unit area with respect to the plate electrode is changed stepwise or continuously in the flow direction of the material gas. Item 2. The thin-film semiconductor manufacturing apparatus according to item 2 or 3. 5. The number of the threshold electrodes per unit area with respect to the flat plate electrode is large in the material supply rate-determining region which is the upstream side in the flow direction of the material gas, and is small in the material depletion region which is the downstream side. The thin-film semiconductor manufacturing apparatus according to claim 4, wherein 6. An apparatus for producing a thin film semiconductor, wherein a strip-shaped member is continuously passed through a plurality of connected plasma CVD devices, and a plurality of different thin film semiconductors are laminated on the strip-shaped member by a plasma CVD method. A part or all of the plurality of plasma CVD apparatuses is the thin film semiconductor manufacturing apparatus according to any one of claims 1 to 5. 7. A strip-shaped member is continuously passed through a plurality of connected plasma CVD devices, and at least one set of n-type, i-type, and p-types are formed on the strip-shaped member by a plasma CVD method.
A thin-film semiconductor manufacturing apparatus for forming type thin film semiconductor layers in this order, at least the p-type thin-film semiconductor layer manufacturing apparatus according to any one of claims 1 to 5. 2. A thin-film semiconductor manufacturing apparatus, comprising: 8. The main component of the p-type thin film semiconductor layer is S.
The thin film semiconductor manufacturing apparatus according to claim 7, wherein the thin film semiconductor is i or Si and is a microcrystal. 9. A strip-shaped member is continuously passed through a plurality of connected plasma CVD apparatuses, and at least one set of n-type, i-type, and p-types are formed on the strip-shaped member by a plasma CVD method.
In a method for producing a thin film semiconductor, in which a p-type thin film semiconductor layer is formed in this order, at least the p-type thin film semiconductor layer is formed by using the thin film semiconductor production apparatus according to any one of claims 1 to 5. Using the p-type thin film semiconductor layer as SiH
A p-type thin film semiconductor layer having a main component of Si or Si and a microcrystal is formed by a material gas selected from a part or all of 4, CH 4, BF 3, and H 2. Method for manufacturing thin film semiconductor. 10. The p-type thin film semiconductor layer is 13.56M.
The thin film semiconductor manufacturing method according to claim 9, wherein the thin film semiconductor is manufactured by using a power supply of a sine wave of Hz. 11. The method for producing a thin film semiconductor according to claim 9, wherein the p-type thin film semiconductor layer is formed at a temperature of 270 ° C. or lower.