JP3017390B2 - Manufacturing method of photovoltaic device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate of a non-single-crystal n-type layer (or p-type layer) containing silicon atoms, a non-single-crystal i-type layer and a non-single-crystal p-type layer (or n-type layer). Pi
The n structure, thickness formed by laminating at least one structure or
The present invention relates to a method for manufacturing a photovoltaic element such as a positive battery or a sensor.

[0002]

2. Description of the Related Art Conventionally, defects existing in a semiconductor are closely related to generation and recombination of electric charges, and deteriorate the characteristics of the device. As a method of compensating for such a defect level, a hydrogen plasma treatment has been proposed. For example, USP
No. 4,113,514 (JI Pankove et al., RCA Sep. 12, 1978) describes a hydrogen plasma treatment of a completed semiconductor device. Also "EF
FECT OF PLASMA TREATMENT OF THE TCO ON a-Si SOLAR
CELL PERFORMANCE ", F. Demichelis et.al., Mat.Res.So
Vol. 258, p9O5, 1992, discloses a method in which a transparent electrode deposited on a substrate is treated with hydrogen plasma, and a solar cell having a pin structure is formed thereon. Furthermore, "HYDR
OGEN-PLASMA REACTION FLUSHING F0R a-Si: H PIN SOL
AR CELL FABRlCATION ", YSTsuo et.al., Mat.Res.Soc.
Symp. Proc. Vol. 149, p471, 1989, shows that the surface of a p-layer is subjected to hydrogen plasma treatment before the i-layer is deposited in a solar cell having a pin structure. In the conventional hydrogen plasma processing as described above, only hydrogen gas is introduced into the chamber,
The hydrogen plasma treatment was performed by activating the hydrogen gas with RF power.

[0003] Hydrogen plasma is applied to a substrate to be treated,
It not only spreads to act on unfinished elements and finished elements, but also spreads throughout the chamber. Since the hydrogen plasma is very active, impurities (such as oxygen, nitrogen,
(Carbon, iron, chromium, nickel, aluminum, etc.).

In addition, hydrogen gas is more difficult to cause discharge than other gases, and plasma using only hydrogen gas cannot perform stable hydrogen plasma treatment because it is more difficult to maintain plasma than other gases. There is a problem.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems. That is, an object of the present invention is to provide a hydrogen plasma processing method in which the incorporation of impurities contained or contained in the chamber wall does not substantially occur, and a method of performing a more stable hydrogen plasma processing. is there.

It is another object of the present invention to provide a method for forming a photovoltaic element in which the semiconductor layer does not substantially peel even when the photovoltaic element is placed at high temperature and high humidity. It is a further object of the present invention to provide a method for forming a photovoltaic element in which a pin semiconductor layer is not easily peeled off even when a pin structure is formed on a flexible substrate.

Still another object of the present invention is to provide a photovoltaic device which suppresses deterioration in characteristics of a photovoltaic element such as separation of a substrate and a semiconductor layer and increase in series resistance when irradiated with light under high temperature and high humidity. An object of the present invention is to provide a method for forming a power element. It is another object of the present invention to provide a photovoltaic element in which the characteristics are not significantly reduced when used at a high temperature.

An object of the present invention is to provide a photovoltaic element in which the diffusion of impurities from the p-type layer to the i-type layer is prevented and the initial efficiency is improved. An object of the present invention is to provide a photovoltaic element that is not easily broken when a reverse bias is applied to the photovoltaic element. An object of the present invention is to provide a p-type layer and p /
In the vicinity of the interface of the i-buffer layer, the distribution of the Group III element of the periodic table is distributed so as to change rapidly, and the moving distance of the photo-excited charge near the interface is increased, so that the photovoltaic element having a large photoelectric conversion efficiency is obtained. It is to provide a power element.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, have found that the above object can be achieved by a method of forming between a p / i buffer layer and a p-type layer. I found it. That is, the present invention provides a non-single-crystal n-type layer (or p-type layer) containing silicon atoms on a substrate,
Non-single-crystal i-type n / i buffer layer (or p / i buffer layer), non-single-crystal i-type layer, non-single-crystal i-type p / i buffer layer (or n / i buffer layer) and non-single crystal A pin structure formed by stacking p-type layers (or n-type layers)
In a method of manufacturing a photovoltaic device having at least one or more stacked layers, the vicinity of the interface where the p / i buffer layer and the p-type layer are in contact with a silicon atom-containing gas that is substantially non-deposited. It is characterized in that plasma treatment is performed with a hydrogen gas containing a gas containing a Group III element in the periodic table.

Further, the present invention provides a method for manufacturing a semiconductor device in the vicinity of the interface between the substrate and the n-type layer (or the vicinity of the interface between the substrate and the p-type layer).
Is plasma-treated with a hydrogen gas containing a silicon atom-containing gas to such an extent that it does not substantially deposit.
Still further, the present invention relates to the vicinity of the interface where the n / i buffer layer and the n-type layer are in contact, the vicinity of the interface where the n / i buffer layer and the i-type layer are in contact, and the relationship between the p / i buffer layer and the i-type layer. The plasma processing is performed on the vicinity of the contacting interface with a hydrogen gas containing a silicon atom-containing gas to such an extent that substantially no deposition occurs.

Further, in the present invention, the silicon atom-containing gas may be SiH ₄ , Si ₂ H ₆ , SiF ₄ , SiFH ₃ , SiF _{2
H 2, SiF 3 H, SiC} l 2 H 2, SiCl 3 H, SiC
Of l _4, it is characterized in that at least one.
Further, the present invention is characterized in that the content of the silicon atom-containing gas with respect to hydrogen gas is 0.1% or less.

[0012]

The above object can be solved by forming a photovoltaic element by depositing a semiconductor layer after performing a hydrogen plasma treatment by adding a silicon-containing gas to a hydrogen gas so as not to substantially contribute to the deposition. is there. The detailed mechanism is not clear at present, but the present inventors consider as follows.

That is, when the hydrogen gas contains a silicon atom-containing gas to such an extent that it does not substantially contribute to the deposition, and the hydrogen plasma treatment is performed, the activated silicon atom-containing gas is adsorbed on the inner wall of the chamber. Acts on oxygen and water to produce stable silicon oxide and the like, which is more stable than adsorbed on the inner wall of the chamber in the form of oxygen or water. As a result, the silicon atom-containing gas is contained to such an extent that it does not substantially contribute to deposition, and when plasma processing is performed, the incorporation of impurities such as oxygen and water adsorbed on the chamber wall surface into the semiconductor is suppressed to a very low level. It is thought that things can be done.

In addition, when hydrogen plasma processing is performed using hydrogen gas containing a small amount of a gas containing silicon atoms, hydrogen atoms are prevented from deeply diffusing into the chamber wall surface on the chamber wall surface, and the chamber wall surface is prevented from being diffused. It is considered that a reaction such as taking out impurities that form a defect level by entering the semiconductor layer from the inside can be suppressed as much as possible.

Although hydrogen gas has a high ionization energy and it is difficult to stably maintain a plasma discharge for a long time, a small amount of a silicon atom-containing gas that easily maintains a plasma discharge is added to the hydrogen gas as in the present invention. By things
It is believed that the maintenance of the plasma discharge of hydrogen gas is facilitated. By applying such a very stable hydrogen plasma discharge to a substrate or element, the uniformity and reproducibility of the hydrogen plasma treatment can be greatly improved. By improving the uniformity and reproducibility of such hydrogen plasma treatment, it is possible to prevent local peeling of semiconductor layers and increase in series resistance under high temperature, high humidity and light irradiation for a long time on substrates and elements that have been subjected to hydrogen plasma treatment. You can do it.

In the hydrogen plasma treatment of the present invention, the direction in which the surface of the substrate has a textured structure and where the textured structure is locally sharply developed is blunted to contain a gas containing silicon atoms. It works for.
As a result, abnormal growth of the semiconductor layer can be substantially prevented even if the semiconductor layer is deposited on the textured substrate subjected to the hydrogen plasma treatment of the present invention. Therefore, when a photovoltaic element having a pin structure is formed, the characteristic unevenness of the photovoltaic element is small, the adhesion between the substrate and the semiconductor layer is excellent,
Further, a photovoltaic element having excellent durability under high temperature and high humidity can be obtained.

When the hydrogen plasma treatment of the present invention is performed near the interface between the p / i buffer layer and the p-type layer, defects near the interface can be reduced, and the movement of the charges excited by light can be easily performed. Is what you do. In particular, silicon atom-containing active species generated by plasma from silicon atom-containing gas to such an extent that substantially no deposition occurs collide with or displace silicon atoms on the surface subjected to hydrogen plasma treatment, and the structural relaxation progresses, and the surface state is reduced. Is to be improved. In particular, when light is irradiated from the p-type layer, many charges excited by light are generated on the p-layer side, so that many defects are likely to be generated on the p-layer side. p
It can be alleviated by performing near the interface between the / i buffer layer and the p-type layer. Also, in the p-type layer which is made p-type with B having a small atomic radius, when the free charge excited by light increases, the diffusion of B is promoted, and the characteristics of the photovoltaic element deteriorate. This can be prevented by performing the hydrogen plasma treatment of the present invention near the interface between the p / i buffer layer and the p-type layer. As a result, in the photovoltaic device that has been subjected to the hydrogen plasma treatment of the present invention, the photovoltaic device is less likely to break when a reverse bias is applied to the photovoltaic device.

Further, the p-type layer and the p / i layer are treated with a hydrogen gas to which a gas containing a Group III element of the periodic table is added.
Since the Group III element of the periodic table can be contained in a very large amount and at a high activation rate near the interface of the buffer layer, the p-type layer can be thinned, and the light applied to the photovoltaic element can be reduced. It can be used more effectively. Further, the moving distance of the minority carrier is increased, and the characteristics of the photovoltaic element are improved.

When the hydrogen plasma treatment of the present invention is performed at the interface between the p / i buffer layer and the i-type layer, defects near the interface can be reduced, and the transfer of charges excited by light can be facilitated. Things. In particular, silicon atom-containing active species generated by plasma from silicon atom-containing gas to such an extent that substantially no deposition occurs collide with or displace silicon atoms on the surface subjected to hydrogen plasma treatment, and the structural relaxation progresses, and the surface state is reduced. Is to be improved.

Further, the hydrogen plasma treatment of the present invention may be performed by n / i
When the process is performed at the interface between the buffer layer and the i-type layer, distortion near the interface between the n / i buffer layer and the i-type layer can be reduced. As a result, it is possible to suppress an increase in localized levels due to light deterioration when light irradiation is performed for a long time. In addition, the photo-excited charges also easily move to the n-type layer and the p-type layer.

Further, when the hydrogen plasma treatment of the present invention is performed at the interface between the n-type layer and the n / i buffer layer, diffusion of impurities from the n-type layer to the i-type layer can be prevented. Although the detailed mechanism is unknown, the present inventors think as follows. When the surface of the n-type layer or the n / i buffer layer is subjected to a hydrogen plasma treatment containing a small amount of the silicon atom-containing gas of the present invention, defects or structural distortion of the surface of the n-type layer or the n / i buffer layer are caused. It is believed that it can be reduced by diffusing active hydrogen plasma into the layer or diffusing silicon atoms contained in trace amounts into vacancies.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail. First, a method and an apparatus for forming a photovoltaic element of the present invention will be described in detail with reference to the drawings. (Hydrogen Plasma Treatment Conditions) FIGS. 1 to 3 show examples of a photovoltaic element of the present invention which has been subjected to hydrogen plasma treatment with a hydrogen gas containing a small amount of a silicon atom-containing gas.

FIG. 1 is a schematic explanatory view of a photovoltaic element having one pin structure. When the photovoltaic element emits light from the side opposite to the substrate, the substrate 190 (support 10
0, reflection layer 101, reflection enhancement layer 102), first n-type layer (or p-type layer) 103, first n / i buffer layer (or p / i buffer layer) 151, first i-type layer 1
04, first p / i buffer layer (or n / i buffer layer) 161, first p-type layer (or n-type layer) 10
5, a transparent electrode 112 and a current collecting electrode 113. When light is irradiated from the substrate side, 100 is a light-transmitting support, 101 is a transparent conductive layer, 102 is an antireflection layer, and 112 is a conductive layer also serving as a reflective layer.

FIG. 2 is a schematic illustration of a photovoltaic element having two pin structures. The photovoltaic element is mounted on a substrate 290.
(Support 200, reflection layer 201, reflection enhancement layer 202),
A first n-type layer (or p-type layer) 203, a first n / i buffer layer (or p / i buffer layer) 251,
Layer 204, the first p / i buffer layer (or n
/ I buffer layer) 261, first p-type layer (or n-type layer) 205, second n-type layer (or p-type layer) 206, second n / i buffer layer (or p / i buffer layer) )
252, second i-type layer 207, second p / i buffer layer (or n / i buffer layer) 262, second p-type layer (or n-type layer) 208, transparent electrode 212, current collecting electrode 2
13. When light is irradiated from the substrate side, 200 is a transparent support, 201 is a transparent conductive layer, 202 is an antireflection layer, and 212 is a conductive layer also serving as a reflective layer.

FIG. 3 is a schematic explanatory view of a photovoltaic element having three pin structures. The photovoltaic element is mounted on a substrate 390.
(Support 300, reflection layer 301, reflection enhancement layer 302),
A first n-type layer (or p-type layer) 303, a first n / i buffer layer (or p / i buffer layer) 351,
Layer 304, the first p / i buffer layer (or n
/ I buffer layer) 361, first p-type layer (or n-type layer) 305, second n-type layer (or p-type layer) 306, second n / i buffer layer (or p / i buffer layer) )
352, a second i-type layer 307, a second p / i buffer layer (or n / i buffer layer) 362, a second p-type layer (or n-type layer) 308, a third n-type layer (or p-type layer) 309, third n / i buffer layer (or p / i
Buffer layer) 353, third i-type layer 310, third p-type layer
/ I buffer layer (or n / i buffer layer) 36
3, third p-type layer (or n-type layer) 311, transparent electrode 3
12, a current collecting electrode 313. When light is irradiated from the substrate side, 300 is a light-transmitting support, 301 is a transparent conductive layer, 302 is an antireflection layer, 312
Is formed of a conductive layer also serving as a reflective layer.

In the present invention, the plasma treatment with a hydrogen gas containing a silicon atom-containing gas and a gas containing a Group III element of the periodic table to such an extent that substantially no deposition occurs is performed by using an interface between the p / i buffer layer and the p-type layer. It is effective to perform it near. The hydrogen flow rate suitable for achieving the object of the present invention is appropriately optimized depending on the size of the processing chamber.
A suitable flow rate is 1 to 2000 sccm. When the hydrogen flow rate is less than 1 sccm, the power for maintaining the plasma discharge increases, the damage to the base slope becomes severe, and impurities are easily taken in from the chamber wall. When the flow rate of hydrogen is more than 2000 sccm, the residence time of the silicon-based active species and the active species of hydrogen in the plasma discharge in the chamber is shortened. The effect of the plasma treatment at the step becomes difficult to appear.

In the hydrogen plasma processing method of the present invention,
The preferable addition amount of the silicon atom-containing gas added to the hydrogen gas is 0.001% to 0.1%.
The addition amount of silicon atom-containing gas to hydrogen gas is
If the amount is less than 0.001%, the effect of the present invention is not exhibited. If the amount is more than 0.1%, the deposition of silicon atoms increases, so that the original effect of the hydrogen plasma treatment is not exhibited.

In the hydrogen plasma processing method of the present invention,
The proportion of the group III element containing gas added to the hydrogen gas is preferably in the range of 0.05 to 3%. By treating the vicinity of the interface between the p-type layer and the p / i buffer layer with a hydrogen plasma containing a Group III element of the periodic table and silicon atoms that do not substantially deposit in this range, The distribution of Group III elements in the periodic table near the interface can be changed sharply. In addition, the hydrogen plasma treatment of the present invention improves the activation rate of the Group III element in the periodic table near the interface, and particularly improves the p-type layer and the p / i buffer layer, which are important for a pin structure photovoltaic power. In the vicinity of the interface, the addition amount and activation rate of Group III elements of the periodic table are increased,
The movement distance of the minority carrier is increased, and the characteristics as a photovoltaic element are improved. When the hydrogen plasma treatment of the present invention is performed on the p / i buffer layer at a relatively low temperature (280 ° C. or lower), the diffusion of Group III of the periodic table into the p / i buffer layer substantially occurs. Infinitely near the very surface of the p / i buffer layer, the periodic table II
It is possible to make the group I element exist at a high concentration and a high activation rate. As described above, in the hydrogen plasma treatment of the present invention, the Group III element of the periodic table can be contained in a very large amount and at a high activation rate near the interface between the p-type layer and the p / i buffer layer. The thickness of the layer can be reduced, and the light applied to the photovoltaic element can be used more effectively.

The energy suitable for generating the hydrogen plasma of the present invention is an electromagnetic wave, especially RF (r
audio frequency), VHF (very
high frequency), MW (microrow)
ave) is a suitable energy. When the hydrogen plasma treatment of the present invention is performed by RF, a preferable frequency range is:
It is in the range of 1 MHz to 50 MHz. When the hydrogen plasma treatment of the present invention is performed with VHF, a preferable frequency range is from 51 MHz to 500 MHz. When the hydrogen plasma treatment of the present invention is performed by MW, a preferable frequency range is from 0.51 GHz to 10 GHz.

In order to effectively perform the hydrogen plasma treatment of the present invention, the degree of vacuum is an important factor, and the preferable range is the energy used for activating the hydrogen gas to which the silicon atom-containing gas is added. Is largely dependent on When the hydrogen plasma treatment is performed in the RF frequency band, the degree of vacuum is preferably in the range of 0.05 Torr to 10 Torr. The preferred degree of vacuum when performing the hydrogen plasma treatment in the VHF frequency band is in the range of 0.0001 Torr to 1 Torr. The preferred degree of vacuum when performing hydrogen plasma processing in the MW frequency band is 0.0001 T
The range is from orr to 0.01 Torr.

In the hydrogen plasma processing of the present invention, the power density supplied into the chamber to generate hydrogen plasma is an important factor for effectively performing the hydrogen plasma processing of the present invention. Such power density depends on the frequency of the electromagnetic wave used. When using the RF frequency band, the power density is 0.01 to 1
W / cm ³ is a preferred range. When the VHF frequency band is used, a preferable range is 0.01 to 1 W / cm ³ . Particularly, in the case of the VHF frequency band, there is a feature that plasma discharge can be maintained in a wide pressure range. When performing hydrogen plasma processing at a high pressure, it is preferable to perform hydrogen plasma processing at a relatively low power density. On the other hand, when performing hydrogen plasma treatment at a low pressure,
It is preferable to carry out at a relatively high power density.
When the hydrogen plasma treatment of the present invention is performed using the MW frequency band, the preferable power density is 0.1 to 10 W / cm ³ . In performing the hydrogen plasma treatment of the present invention, there is a close relationship between the power density and the hydrogen plasma treatment time, and when the power density is high, it is preferable that the hydrogen plasma treatment time be relatively short. is there.

In the hydrogen plasma processing of the present invention, the substrate temperature during the hydrogen plasma processing is a very important factor for making the effects of the present invention effective. In the case where the hydrogen plasma treatment is performed using the RF frequency band, the substrate temperature is preferably relatively high, and the preferable temperature range is 100 to 400 ° C. When the hydrogen plasma treatment of the present invention is performed using the VHF or MW frequency band, it is preferable that the substrate temperature be relatively low. In this case, 50 to 300 ° C. is a preferable temperature range.
Further, the substrate temperature during the hydrogen plasma treatment of the present invention also depends closely on the power density supplied into the chamber, and when the supplied power density is relatively high, the substrate temperature is performed at a lower temperature. Is preferred.

When performing the hydrogen plasma treatment of the present invention, the above-described power density, gas flow rate, substrate temperature, pressure, etc.
It may be changed with respect to the processing time. Usually, a substrate has many defects and many impurities near the surface. Therefore, the hydrogen plasma treatment is preferably performed at a relatively high power density and a high pressure at the start of the treatment.

In the hydrogen plasma treatment of the present invention, the silicon atom-containing gas added to the hydrogen gas is Si gas.
H ₄ , Si ₂ H ₆ , SiF ₄ , SiF ₃ H, SiF ₂ H ₂ , S
iF ₃ H, Si ₂ FH 5, SiCl ₄ , SiClH ₃ , Si
Silicon hydride compounds or silicon halide compounds such as Cl ₂ H ₂ and SlClH ₃ are suitable. These silicon atom-containing gases may be added alone to the hydrogen gas, or may be added in combination of two or more. In particular, the mixing ratio of the silicon atom-containing gas containing a halogen atom is preferably larger than that of the silicon atom-containing gas not containing a halogen atom.

(Forming Method and Apparatus) A method for forming a photovoltaic element of the present invention and a forming apparatus suitable for the method will be described. An example of the forming apparatus is shown in a schematic explanatory view of FIG. 4, a forming apparatus 400 includes a load chamber 401, transfer chambers 402, 403, and 404, an unload chamber 405, and gate valves 406, 407, 408, and 40.
9, substrate heating heaters 410, 411, 412, substrate transport rails 413, n-type layer (or p-type layer) deposition chamber 417, i-type layer deposition chamber 418, p-type layer (or n-type layer) deposition chamber 419 , Plasma forming cups 420, 421, power supplies 422, 423, 42
4. Microwave introduction window 425, waveguide 426, gas introduction pipes 429, 449, 469, valves 430, 431,
432, 433, 434, 441, 442, 443, 4
44, 450, 451, 452, 453, 454, 45
5, 461, 462, 463, 464, 465, 47
0, 471, 472, 473, 474, 481, 48
2, 483, 484, mass flow controller 43
6, 437, 438, 439, 456, 457, 45
8, 459, 460, 476, 477, 478, 47
9, a shutter 427, a bias rod 428, a substrate holder 490, an exhaust device (not shown), a microwave power source (not shown), a vacuum gauge (not shown), a control device (not shown), and the like.

A method for forming a photovoltaic element to which the hydrogen plasma processing method of the present invention is applied is performed as follows using a forming apparatus shown in FIG. All the chambers of the deposition apparatus 400 are pulled up to a vacuum of 10 ⁻⁶ Torr or less by a turbo molecular pump (not shown) connected to each chamber. When the hydrogen plasma treatment of the present invention is performed by RF, it is performed as follows. A base plate on which a reflective layer of silver or the like is deposited on a stainless steel support and a reflection-enhancing layer of zinc oxide or the like is further deposited is attached to a base holder 490. The substrate holder 4
90 is put into the load chamber 401. The door of the load chamber 401 is closed, and the load chamber 401 is raised to a predetermined degree of vacuum by a mechanical booster pump / rotary pump (MP / RP) (not shown). When the load chamber reaches a predetermined degree of vacuum, the MP / RP is switched to a turbo molecular pump to raise the degree of vacuum to 10 ^-6 Torr or less. Load chamber is 10 ^-6 Torr
When the degree of vacuum becomes as follows, the gate valve 406 is opened, the substrate holder 490 on the substrate transport rail 413 is moved to the transport chamber 402, and the gate valve 406 is opened.
Close. The substrate heating heater 410 of the transfer chamber 402 is raised so that the substrate holder 490 does not hit. The position of the substrate holder is determined so that the substrate comes directly under the heater. The substrate heating heater 410 is lowered, and the substrate is put into the n-type layer deposition chamber.

[0037] change the substrate temperature to a temperature suitable for deposition of the n-type layer, SiH for n-type layer deposition _4, Si ₂ H ₆ or the like Periodic Table V for silicon atom-containing gas and n-type layer deposition Group element containing gas with valve 443, mass flow controller 43
8. Introduce into the deposition chamber 417 via the valve 433. It is also preferable that the flow rate of the hydrogen gas is appropriately adjusted according to the n-type layer. In this way, the source gas for depositing the n-type layer is introduced into the deposition chamber 417, and the degree of opening and closing of the exhaust valve (not shown) is changed to make the inside of the deposition chamber 417 a desired degree of vacuum of 0.1 to 10 Torr. Then, the RF power is supplied from the RF power supply 422 to the plasma forming cup 420.
Power is applied to cause a plasma discharge and maintain the discharge for a desired time. In this manner, an n-type semiconductor layer is deposited on the substrate to a desired thickness.

After the deposition of the n-type layer is completed, the introduction of the source gas into the deposition chamber 417 is stopped, and the inside of the chamber is purged with hydrogen gas or helium gas. After sufficient purging, supply of hydrogen gas or helium gas is stopped, and the interior of the deposition chamber is
Raise to 0 ^-6 Torr. The gate valve 407 is opened, the substrate holder 490 is moved to the transfer chamber 403, and the gate valve 407 is closed. The position of the substrate holder is adjusted so that the substrate can be heated by the substrate heating heater 411. A substrate heating heater is brought into contact with the substrate to heat the substrate to a predetermined temperature. At the same time, an inert gas such as a hydrogen gas or a helium gas is introduced into the deposition chamber 418. Further, it is preferable that the degree of vacuum at that time is the same as that at the time of depositing the n / i buffer layer. When the substrate temperature reaches a desired temperature, the gas for heating the substrate is stopped, and the source gas for depositing the n / i buffer layer is supplied to the deposition chamber 418 from the gas supply device. For example, hydrogen gas, silane gas, and germane gas are respectively supplied to the valve 46.
2, 463 and 464 are opened, and the desired settings are made with the mass flow controllers 457, 458 and 459, and the valve 45 is opened.
2, 453, 454 and 450 are opened to open a gas introduction pipe 449.
To the deposition chamber 418. At the same time, the supply gas is evacuated by a diffusion pump (not shown) so that the degree of vacuum in the deposition chamber 418 becomes a desired pressure. When the degree of vacuum in the chamber 418 is stabilized at a desired degree,
A desired power is introduced from a not-shown RF power supply into a bias rod for applying a bias. Then, n is applied by RF plasma CVD.
/ I Deposit buffer layer. The n / i buffer layer is
It is preferable to deposit at a lower deposition rate than the i-type layer deposited thereafter.

Next, the substrate is heated to a predetermined temperature for depositing the i-type layer. It is preferable to open the valve 461 and set a desired flow rate of an inert gas such as hydrogen gas or helium gas by a mass flow controller, and heat the substrate while opening the valves 451 and 450. Further, it is preferable that the degree of vacuum at that time is the same as that for depositing the i-type layer.

When the substrate temperature reaches a desired temperature, the gas for heating the substrate is stopped, and the source gas for depositing the i-type layer is supplied to the deposition chamber 418 from the gas supply device. For example, hydrogen gas, silane gas, and germane gas are opened at valves 462, 463, and 464, respectively, and the desired flow rates are set by mass flow controllers 457, 458, and 459. To the deposition chamber 418. At the same time, the supply gas is evacuated by a diffusion pump (not shown) so that the degree of vacuum in the deposition chamber 418 becomes a desired pressure.
When the degree of vacuum in the chamber 418 is stabilized at a desired degree of vacuum, desired power is introduced from a microwave power supply (not shown) into the deposition chamber 418 via the waveguide 426 and the microwave introduction window 425. Simultaneously with the introduction of the microwave energy, as shown in the enlarged view of the deposition chamber 418, an external DC, RF or VH
It is also preferred to introduce the desired bias power from the F power supply 424 into the deposition chamber 418. Thus, an i-type layer is deposited to a desired thickness. When the i-type layer has been deposited to a desired thickness, the application of microwave power and bias is stopped. If necessary, the deposition chamber 418
The inside is purged with an inert gas such as hydrogen gas or helium gas.

Thereafter, a p / i buffer layer is deposited to a desired thickness in the same manner as the deposition of the n / i buffer layer. Thereafter, if necessary, the inside of the deposition chamber 418 is purged with an inert gas such as hydrogen gas or helium gas. The hydrogen plasma treatment of the present invention on the p / i buffer layer is performed as follows. In the chamber, hydrogen gas, silicon atom-containing gas and Group III element containing gas required for performing the hydrogen plasma treatment of the present invention are supplied with valves 461, 462, 463, mass flow controllers 456, 457, 458, and valve 451. 452,
453, a predetermined flow rate is introduced into the deposition chamber 418 via the valve 450. The inside of the deposition chamber 418 is set to a desired degree of vacuum by changing the opening / closing degree of an exhaust valve (not shown). When the degree of vacuum in the chamber 418 is stabilized, RF power is introduced from the RF power supply 424 to the bias bar 428 to generate plasma. Thus, the hydrogen plasma treatment of the present invention is performed for a predetermined time. During hydrogen plasma treatment, the flow rate of hydrogen gas, the flow rate of silicon atom-containing gas, RF power,
It is desirable to appropriately change the substrate temperature and the like. Preferred forms of these parameters include:
The first is to increase the hydrogen flow rate and decrease the hydrogen flow rate over time. As a form of a change in the flow rate of the silicon atom-containing gas, the flow rate of the silicon atom-containing gas is initially small and the flow rate of the silicon atom-containing gas is increased with time. A preferred form of change is that the RF power is initially high and then reduced over time.

After the hydrogen plasma treatment of the present invention is completed,
The inside of the deposition chamber is purged, the exhaust is changed from the diffusion pump to the turbo molecular pump, and the degree of vacuum in the deposition chamber is set to 10 ⁻⁶ T.
The degree of vacuum is set to orr or lower. At the same time, the heater for heating the substrate is raised so that the substrate holder can be moved. The gate valve 408 is opened, the base holder is moved from the transfer chamber 403 to the transfer chamber 404, and the gate valve 408 is closed.

The substrate holder is heated to a substrate heater 412.
, And the substrate is heated by the heater 412 for heating the substrate. It is more preferable that the substrate be heated by changing the exhaust gas from the turbo molecular pump to MP / RP and flowing an inert gas such as a hydrogen gas or a helium gas to a pressure at the time of deposition of the p-type layer during heating. is there. When the substrate temperature is stabilized at a desired substrate temperature, supply of a substrate heating gas such as a hydrogen gas or an inert gas for substrate heating is stopped, and a source gas for p-type layer deposition, for example, H ₂ , SiH ₄ , BF _{3, and} other gases containing a Group III element in the periodic table are supplied to valves 482, 483, and 48.
4, open the mass flow controllers 477, 478,
The valves 472, 473, and 474 are further opened via 479 to supply a desired flow rate to the deposition chamber 419 through the gas introduction pipe 469. The exhaust valve is adjusted so that the internal pressure of the deposition chamber 419 reaches a desired degree of vacuum. When the internal pressure of the deposition chamber 419 is stabilized at a desired degree of vacuum, RF power is supplied from the RF power source 423 to the plasma forming cup. The p-type layer is then deposited for the desired time. After the deposition, the supply of the RF power and the source gas is stopped, and the inside of the deposition chamber is sufficiently purged with an inert gas such as a hydrogen gas or a helium gas. After completion of the purging, the exhaust gas is changed from MP / RP to a turbo molecular pump for 1 minute.
Evacuate to a degree of vacuum of 0 ^-6 Torr or less. At the same time, the heater 412 for heating the substrate is raised, the gate valve 409 is opened, and the substrate holder 490 is moved to the unload chamber 4.
Move to 05. The gate valve 409 is closed, and when the temperature of the substrate holder becomes 100 ° C. or less, the door of the unload chamber is opened and taken out. Thus, a pin semiconductor layer is formed on the substrate subjected to the hydrogen plasma treatment of the present invention. The substrate on which the pin semiconductor layer is formed is set in a vacuum evaporator for depositing a transparent electrode, and a transparent electrode is formed on the semiconductor layer. Next, the photovoltaic element on which the transparent electrode is formed is set in a vacuum evaporator for depositing a current collecting electrode, and the current collecting electrode is deposited. Thus, a photovoltaic element is formed.

When the hydrogen plasma treatment of the present invention is performed by MW, for example, it is performed as follows. The gate valve is opened, the substrate holder 490 is moved to the transfer chamber 403, and the gate valve is closed. The position of the substrate holder is determined so that the substrate comes directly under the heater. The substrate heating heater 411 is lowered, and the substrate is put into the i-type layer deposition chamber. The substrate temperature is raised to a desired substrate temperature by the substrate heater 411. MP / R turbo molecular pump
Switching to P, hydrogen gas and silicon atom-containing gas necessary for performing the hydrogen plasma treatment of the present invention in the chamber are supplied to valves 461 and 462 and mass flow controller 45.
A predetermined flow rate is introduced into the deposition chamber 418 via 6, 457, valves 451, 452, and valve 450. The inside of the deposition chamber 418 is set to a desired degree of vacuum by changing the opening / closing degree of an exhaust valve (not shown). When the degree of vacuum in the chamber 418 is stabilized, MW power is introduced from a MW power supply (not shown) into the deposition chamber 418 through the microwave introduction window 425 to generate plasma. Thus, the hydrogen plasma treatment of the present invention is performed for a predetermined time. Depending on the surface condition of the substrate and the condition of the inner wall of the chamber, the flow rate of the hydrogen gas, the flow rate of the silicon atom-containing gas,
It is desirable to appropriately change MW power, substrate temperature, and the like. A preferred form of variation of these parameters is to initially increase the hydrogen flow and decrease the hydrogen flow over time. As a form of a change in the flow rate of the silicon atom-containing gas, the flow rate of the silicon atom-containing gas is initially small and the flow rate of the silicon atom-containing gas is increased with time. A preferred form of change is that the MW power is initially high and then reduced over time. When performing the hydrogen plasma treatment of the present invention with VHF, it is preferable to perform the same treatment as with MW.

Further, it is also preferable to perform a hydrogen plasma treatment on the vicinity of the interface between the substrate and the n-type layer with a hydrogen gas containing a gas that does not substantially deposit a silicon atom-containing gas. In order to perform hydrogen plasma treatment near the interface between the substrate and the n-type layer, the substrate is transferred to the n-type layer deposition chamber or the i-type layer deposition chamber in the above-described procedure, and the substrate is maintained at a predetermined substrate temperature. In the above procedure, a predetermined flow rate of the silicon atom-containing gas and the hydrogen gas is introduced into the deposition chamber. The pressure is adjusted by the pressure adjusting valve so that the degree of vacuum is appropriate for the type of the introduced power such as RF, VHF and / or MW power. A plasma discharge is generated by introducing RF, VHF or / and MW power, and the hydrogen plasma treatment of the present invention is performed on the substrate for a predetermined time.

The characteristics of the photovoltaic element are further improved by performing a plasma treatment on the vicinity of the interface between the n / i buffer layer and the i-type layer with a hydrogen gas containing silicon gas containing gas that does not contribute to deposition. Although it is improved, the hydrogen plasma treatment of the present invention is performed on the n / i-type layer as follows. A predetermined amount of hydrogen gas and a gas containing silicon atoms necessary for performing the hydrogen plasma treatment of the present invention are supplied to the deposition chamber 418 through valves 461 and 462, mass flow controllers 456 and 457, valves 451 and 452, and a valve 450. To be introduced. The inside of the deposition chamber 418 is set to a desired degree of vacuum by changing the opening / closing degree of an exhaust valve (not shown). When the degree of vacuum in the chamber 418 is stabilized, RF power is introduced from the RF power source 424 to the bias source 428 to generate plasma. Thus, the hydrogen plasma treatment of the present invention is performed for a predetermined time. Depending on the surface state of the substrate and the state of the inner wall of the chamber, it is desirable to appropriately change the flow rate of the hydrogen gas, the flow rate of the silicon atom-containing gas, the RF power, the base slope temperature, etc. during the hydrogen plasma treatment. is there. A preferred form of variation of these parameters is to initially increase the hydrogen flow and decrease the hydrogen flow over time. As a form of a change in the flow rate of the silicon atom-containing gas, the flow rate of the silicon atom-containing gas is initially small and the flow rate of the silicon atom-containing gas is increased with time. A preferred form of change is that the RF power is initially high and then reduced over time.

The hydrogen plasma treatment of the present invention is performed on the i-type layer as follows. In the chamber, hydrogen gas and silicon atom-containing gas necessary for performing the hydrogen plasma treatment of the present invention are supplied to valves 461 and 462 and mass flow 45.
A predetermined flow rate is introduced into the deposition chamber 418 via 6, 457, valves 451, 452, and valve 450. The inside of the deposition chamber 418 is set to a desired degree of vacuum by changing the opening / closing degree of an exhaust valve (not shown). When the degree of vacuum in the chamber 418 becomes stable, the RF power is supplied from the RF power source 424 to the bias rod 42.
8 to generate plasma. Thus, the hydrogen plasma treatment of the present invention is performed for a predetermined time. Depending on the surface state of the substrate and the state of the inner wall of the chamber, it is desirable to appropriately change the flow rate of the hydrogen gas, the flow rate of the silicon atom-containing gas, the RF power, the substrate temperature, etc. during the hydrogen plasma treatment. . A preferred form of variation of these parameters is to initially increase the hydrogen flow and decrease the hydrogen flow over time. As a form of a change in the flow rate of the silicon atom-containing gas, the flow rate of the silicon atom-containing gas is initially small and the flow rate of the silicon atom-containing gas is increased with time. A preferred form of change is that the RF power is initially high and then reduced over time.

In the above-described method for forming a photovoltaic element for performing a hydrogen plasma treatment according to the present invention, the gas cylinder may be replaced with a necessary gas cylinder as needed. In that case, it is preferable that the gas line be sufficiently heated and purged. A photovoltaic element in which a plurality of pin semiconductor layers are stacked can be formed by performing a desired number of depositions in the n-type layer deposition chamber, the i-type layer deposition chamber, and the p-type layer deposition chamber of the forming apparatus 400. Things.

Next, the components of the photovoltaic element will be described in detail. (Substrate) As a material of the support preferably used in the present invention, a material having little deformation and distortion at a temperature required for forming a deposited film, having a desired strength, and having conductivity is preferably used. A support that does not decrease the adhesion of the reflective layer or the reflection-enhancing layer to the support even when the hydrogen plasma treatment of the present invention is performed after depositing the reflection layer or the reflection-enhancing layer is preferable.

Specifically, thin films of metals such as stainless steel, aluminum and its alloys, iron and its alloys, copper and its alloys and their composites, and metal thin films of different materials and / or SiO _{2 on} their surfaces, Si ₃ N ₄ , Al ₂
O ₃ , AlN or other insulating thin film that has been subjected to surface coating by sputtering, vapor deposition, plating, etc., or a heat-resistant resin sheet such as polyimide, polyamide, polyethylene terephthalate, epoxy, or glass fiber, Carbon fiber, boron fiber, metal fiber, etc., the surface of which has been subjected to a conductive treatment by plating, vapor deposition, sputtering, coating, or the like with a simple metal or alloy, and a transparent conductive oxide on the surface. .

In addition, the thickness of the support may be set as much as possible in consideration of cost, storage space, and the like as long as the thickness is within a range where the curved shape formed during the movement of the support is strong enough to maintain the strength. Thinner is desirable. Specifically, it is preferably 0.01 mm to 5 mm, more preferably 0.02 mm
The thickness is desirably from 2 mm to 2 mm, optimally from 0.05 mm to 1 mm. However, when a thin film of metal or the like is used, a desired strength is easily obtained even if the thickness is relatively thin.

The width of the support is not particularly limited and is determined by the size of the vacuum vessel and the like. The length of the support is not particularly limited, and may be a length that can be wound into a roll, or may be a longer one that is made longer by welding or the like. Good.

In the present invention, the support is heated and cooled in a short time.
However, it is preferable that the temperature distribution spreads in the longitudinal direction of the support.
Less heat conduction in the direction of support movement
It is desirable that the temperature of the support surface follows the heating and cooling.
For this purpose, it is preferable that the thermal conductivity is large in the thickness direction. Support
To increase the heat conduction in the direction of movement
Can be made thinner, and if the support is uniform, (heat
Conduction) × (thickness) is preferably 1 × 10 ^-1W / K or less,
More preferably 0.5 × 10^-1W / K or less
desirable.

(Reflection Layer) As a material of the reflection layer, Ag,
Au, Pt, Ni, Cr, Cu, Al, Ti, Zn, M
Metals such as o and W or alloys thereof are listed, and thin films of these metals are formed by vacuum evaporation, electron beam evaporation, sputtering, or the like. Also, care must be taken that the formed metal thin film does not become a resistance component with respect to the output of the photovoltaic element, and the sheet resistance of the reflective layer is preferably 50Ω or less, more preferably 10Ω or less. Is desirable.

When the support is translucent and the photovoltaic element is irradiated with light from the translucent support, it is preferable to form a translucent conductive layer instead of the reflective layer. Things. As a light-transmitting conductive layer suitable for such a purpose, tin oxide, indium oxide, an alloy thereof, or the like is suitable. Further, it is preferable that these light-transmitting conductive layers be deposited to a thickness that satisfies antireflection conditions. The sheet resistance of these translucent conductive layers is preferably 50Ω or less, more preferably 10Ω or less.
It is desirable that it be less than Ω.

(Reflection Increasing Layer) The reflection increasing layer desirably has a light reflectance of 85% or more so that the reflected light from the substrate that has passed through the semiconductor layer is efficiently absorbed in each semiconductor layer. Further, the sheet resistance value is desirably 100Ω or less so that the output of the photovoltaic element does not become a resistance component. As a material having such _{characteristics, SnΟ 2, In 2 O 3} , ZnΟ, CdΟ, Cd 2 S
Metal oxides such as nO ₄ and ITO (In ₂ Ο ₃ + SnO ₂ ) are exemplified. In the photovoltaic element, the reflection increasing layer is laminated in contact with the p-type layer or the n-type layer, and it is necessary to select a layer having good mutual adhesion. Further, it is preferable that the reflection enhancing layer is deposited to have a thickness that meets the conditions for increasing the reflection. As a method for forming the reflection increasing layer, a resistance heating evaporation method, an electron beam heating evaporation method, a sputtering method, a spray method, or the like can be used, and is appropriately selected as desired.

(I-type layer) In particular, in a photovoltaic device using a Group IV or Group IV alloy amorphous semiconductor material,
The i-type layer used for the in-junction is an important layer that generates and transports carriers with respect to irradiation light. For an i-type layer, only p
Type, only n-type layers can be used. The amorphous semiconductor material contains a hydrogen atom (H, D) or a halogen atom (X), and has an important function.

The hydrogen atoms (H, D) or the halogen atoms (X) contained in the i-type layer work to compensate for dangling bonds in the i-type layer, and the carrier in the i-type layer is To improve the product of the mobility and the lifetime. Also p
It has a function of compensating the interface state of each interface of the type layer / i-type layer and the n-type layer / i-type layer, and has an effect of improving the photovoltaic power, the photocurrent and the photoresponsiveness of the photovoltaic element. It is. The number of hydrogen atoms and / or halogen atoms contained in the i-type layer is 1 to
40 at% is mentioned as the optimum content. In particular, p
A preferred distribution form is one in which a large amount of hydrogen atoms and / or halogen atoms are distributed on each interface side of the n-type layer / i-type layer and the n-type layer / i-type layer. The content of atoms and / or halogen atoms is preferably 1.1 to 2 times the content in the bulk as a preferred range. Further, it is preferable that the content of hydrogen atoms and / or halogen atoms is changed in accordance with the content of silicon atoms.

When the photovoltaic element of the present invention has a plurality of pin structures, it is preferable to stack the i-type layers in order from the light incident side such that the band gap of the i-type layers becomes smaller. Amorphous silicon or amorphous silicon carbide is used for the i-type layer having a relatively wide band gap, and amorphous silicon germanium is used for the i-type semiconductor layer having a relatively narrow band gap. Amorphous silicon and amorphous silicon germanium can be divided into a-Si: H, a-Si: F, a
-Si: H: F, a-SiGe: H, a-SiGe:
F, a-SiGe: H: F, etc.

When amorphous silicon germanium is used as the i-type layer, it is preferable to change the germanium content in the thickness direction of the i-type layer. In particular, it is a preferable distribution form of germanium that the germanium content continuously decreases in the direction of the n-type layer and / or the p-type layer. The state of distribution of germanium atoms in the layer thickness is
This can be performed by changing the flow rate ratio of the germanium-containing gas contained in the source gas. As a method of changing the content of germanium atoms in the i-type layer by the MW plasma CVD method, in addition to a method of changing a flow ratio of a germanium-containing gas, a method of changing a flow rate of a hydrogen gas as a diluent gas of a source gas is also used. This can be done in the same way. By increasing the amount of hydrogen dilution, the germanium content in the deposited film (i-type layer) can be increased.

The hydrogen plasma treatment of the present invention particularly improves the electrical connection between a so-called graded band gap layer in which germanium atoms are continuously changed and a buffer layer in contact with the so-called graded band gap layer. is there. More specifically, for example, a pin suitable for the photovoltaic device of the present invention is used.
An example of the junction i-type semiconductor layer is i-type hydrogenated amorphous silicon (a-Si: H).
The optical band gap (Eg) is 1.60 eV to 1.60 eV.
85 eV, hydrogen atom content (CH) is 1.0 to 2
5.0%, AM1.5, 100 mW / cm ² , the photoelectric conductivity (σp) under simulated sunlight irradiation is 1.0 × 10 ⁻⁵ S / c.
m or more, and the dark conductivity (σd) is 1.0 × 10 ⁻⁹ S / cm
Hereafter, Constant Photocurrent Method (CPM)
It is preferable that the inclination of the Urbach tail due to the above is 55 meV or less and the localized level density is 10 ¹⁷ / cm ³ or less.

The semiconductor material amorphous silicon germanium constituting the i-type semiconductor layer having a relatively narrow band gap of the photovoltaic element of the present invention has an optical band gap (Eg) of 1.20 eV as a characteristic. ~ 1.60e
V, the content of hydrogen atoms (CH) is 1.0 to 25%, the slope of the Urbach tail by the constant photocurrent method (CPM) is 55 meV or less, and the localized level density is 10 ¹⁷ cm ³ or less. Are preferred.

The i-type layer suitable for the present invention is preferably deposited under the following conditions. The amorphous semiconductor layer is preferably deposited by RF, VHF or MW plasma CVD. In the case of deposition by RF plasma CVD, the substrate temperature is 100 to 350 ° C., the degree of vacuum in the deposition chamber is 0.05 to 10 Torr, and the RF frequency is 1 to 50 MHz. Especially RF
Is suitably 13.56 MHz. The RF power supplied to the deposition chamber is 0.01 to 5 W / cm ²
Is a preferable range. The preferable range of the self-bias applied to the substrate by the RF power is 0 to 300.

When depositing by VHF plasma CVD, the substrate temperature is 100 to 450 ° C., the degree of vacuum in the deposition chamber is 0.0001 to 1 Torr, and the frequency of VHF is 6
0 to 500 MHz is a suitable range. Particularly, the frequency of VHF is suitably 100 MHz. The VHF power supplied into the deposition chamber is preferably in the range of 0.01 to 1 W / cm ³ . The preferable range of the self-bias applied to the substrate by the VHF power is 10 to 1000 V. In addition, the characteristics of the deposited amorphous film are improved by introducing DC or RF into the deposition chamber by overlapping with VHF or separately providing a bias rod. When introducing a DC bias using a bias bar,
It is preferred that the bias rod be positive. When the DC bias is introduced to the substrate side, it is preferable to introduce the DC bias so that the substrate side becomes a negative electrode. When introducing an RF bias, the RF
It is preferable to reduce the area of the electrode into which the gas is introduced.

In the case of deposition by the MW plasma CVD method, the substrate temperature is 100 to 450 ° C., the degree of vacuum in the deposition chamber is 0.0001 to 0.05 Torr, and the frequency of the MW is 501 MHz to 10 GHz. . In particular, the MW frequency is suitably 2.45 GHz. The MW power input into the deposition chamber is 0.01 to 1 W / c.
m ³ is a suitable range. MW power is optimally introduced into the deposition chamber via a waveguide. Further, in addition to the MW, a bias rod is separately provided to introduce DC or RF into the deposition chamber, thereby improving the characteristics of the deposited amorphous film. When a DC bias is introduced using a bias bar, it is preferred that the bias bar be positive. When the DC bias is introduced to the substrate side, it is preferable to introduce the DC bias so that the substrate side becomes a negative electrode. When introducing an RF bias, it is preferable to make the area of the electrode into which RF is introduced smaller than the substrate area.

For deposition of the i-type layer suitable for the plasma treatment of the present invention, a silane-based source gas such as SiH ₄ , Si ₂ H ₆ , SiF ₄ , or SiF ₂ H ₂ is suitable. In order to widen the band gap, it is preferable to add a gas containing carbon, nitrogen or oxygen. The carbon, nitrogen or oxygen containing gas is more preferably contained in the p-type layer than in the i-type layer.
It is preferable that a large amount be contained near the mold layer and / or the n-type layer. By doing so, the open-circuit voltage can be improved without impairing the traveling properties of charges in the i-type layer. As the carbon-containing gas, C
_n H _{2n + 2} , C _n H _2n , C ₂ H _{2 and the} like are suitable. As the nitrogen-containing gas, N ₂ , NO, N ₂₀ , NO ₂ , NH _{3 and the} like are suitable. O ₂ , CO ₂ , O _3, etc. are suitable as the oxygen-containing gas. Further, a plurality of these gases may be introduced in combination. A suitable amount of the source gas for increasing the band gap is 0.1 to 50%.

Further, the properties of the i-type layer are improved by adding an element of Group III and / or Group V of the periodic table. As the Group III elements of the periodic table, B,
Al, Ga and the like are suitable. In particular, when B is added, it is preferable to use a gas such as B ₂ H ₆ or BF ₃ . In addition, as the Group V element of the periodic table,
N, P, As, etc. are suitable. Particularly when P is added, PH ₃ is mentioned as a suitable one. The suitable amount of the Group III and / or Group V element of the periodic table added to the i-type layer is 0.1 to 1000 ppm.

For the i-type layer, the n / i buffer layer and p
By providing the / i buffer layer, the characteristics of the photovoltaic element are improved. As the buffer layer,
A semiconductor layer similar to the i-type layer can be used.
It is preferable to deposit at a lower deposition rate than the mold layer. As the buffer layer, a semiconductor having a wider band gap than the i-type layer is suitable. The band gap is
It is preferred that it be smooth and continuous from the i-type layer to the buffer layer. As a method for continuously changing the band gap in the buffer layer, the band gap can be narrowed by increasing the content of germanium atoms contained in a silicon-based non-single-crystal semiconductor. On the other hand, the band gap can be continuously increased by increasing the content of carbon atoms, oxygen atoms, and / or nitrogen atoms contained in a silicon-based non-single-crystal semiconductor. The ratio of the narrowest band gap to the widest band gap is 1.01 to 1.
A preferred range is 5.

When an element of Group III and / or Group V of the periodic table is added to the buffer layer, an element of Group III of the periodic table is added to the n / i buffer layer and p / i
It is preferable to add a Group V element of the periodic table to the buffer layer. By doing so, it is possible to prevent a decrease in characteristics due to diffusion of impurities from the n-type layer and / or the p-type layer into the i-type layer.

(N-type layer, p-type layer) The p-type layer or the n-type layer is also an important layer that affects the characteristics of the photovoltaic device of the present invention. Examples of the amorphous material (denoted as a-) of the p-type layer or the n-type layer (it goes without saying that a microcrystalline material (denoted as μc-) are also included in the range of the amorphous material). a-Si: H, a-Si: HX, a-SiC: H,
a-SiC: HX, a-SiGe: H, a-SiGe
C: H, a-SiO: H, a-SiN: H, a-SiO
N: HX, a-SiOCN: HX, μc-Si: H, μ
c-SiC: H, μc-Si: HX, μc-SiC: H
X, μc-SiGe: H, μc-SiO: H, μc-S
iGeC: H, μc-SiN: H, μc-SiON: H
X, μc-SiOCN: HX, p-type valence electron control agent (Group III atom B, Al, Ga, In, TI in the periodic table)
And n-type valence electron controlling agents (Group V atoms P, As,
Sb, Bi) are added at a high concentration, and a polycrystalline material (denoted as poly-) is, for example, po
ly-Si: H, poly-Si: HX, poly-S
iC: H, poly-SiC: HX, poly-SiG
e: H, poly-Si, poly-SiC, poly
-SiGe, etc. with p-type valence electron controlling agent (Periodic Table III
Group atom B. Al, Ga, In, Tl) and a material to which an n-type valence electron controlling agent (atom P, As, Sb, Bi in the periodic table, group V atom) is added at a high concentration.

In particular, the p-type layer or the n-type layer on the light incident side includes:
A crystalline semiconductor layer with low light absorption or an amorphous semiconductor layer with a wide band gap is suitable. Periodic Table No. for p-type layer
The optimum amount of the group III atom and the group V atom in the n-type layer is 0.1 to 50 at%. Hydrogen atoms (H, D) or halogen atoms contained in the p-type layer or the n-type layer work to compensate for dangling bonds of the p-type layer or the n-type layer, and doping efficiency of the p-type layer or the n-type layer. Is to improve. A hydrogen atom or a halogen atom added to the p-type layer or the n-type layer is 0.1 to
40 at% is mentioned as the optimum amount. In particular, when the p-type layer or the n-type layer is crystalline, the optimum amount of hydrogen atoms or halogen atoms is 0.1 to 8 at%. And p
A preferred distribution form is one in which a large amount of hydrogen atoms and / or halogen atoms are distributed on each interface side of the n-type layer / i-type layer and the n-type layer / i-type layer. The content of atoms and / or halogen atoms is preferably 1.1 to 2 times the content in the bulk as a preferred range. By increasing the content of hydrogen atoms or halogen atoms in the vicinity of each interface between the p-type layer / i-type layer and the n-type layer / i-type layer, the defect level and mechanical strain near the interface are reduced. Accordingly, the photovoltaic power and the photocurrent of the photovoltaic device of the present invention can be increased.

The p-type layer and the n-type layer of the photovoltaic element preferably have an activation energy of 0.2 eV or less, and most preferably have an activation energy of 0.1 eV or less. The specific resistance is preferably 100 Ωcm or less, and most preferably 1 Ωcm or less. Further, the layer thickness of the p-type layer and the n-type layer is 1 to
50 nm is preferred, and 3 to 10 nm is optimal. Group IV and I suitable as the semiconductor layer of the photovoltaic device of the present invention
In order to form a group V alloy-based amorphous semiconductor layer, the most preferable manufacturing method is a microwave plasma CVD method, and the next most preferable manufacturing method is an RF plasma CVD method.

In the microwave plasma CVD method, a material gas such as a source gas or a diluent gas is introduced into a deposition chamber,
While evacuating by a vacuum pump, the internal pressure of the deposition chamber is kept constant, microwaves oscillated by a microwave power supply are guided by a waveguide, and introduced into the deposition chamber through a dielectric window (alumina ceramics or the like). Is a method of generating a plasma of a material gas and decomposing the same to form a desired deposited film on a substrate disposed in a deposition chamber, and forms a deposited film applicable to a photovoltaic device under a wide range of deposition conditions. be able to.

As a source gas suitable for depositing the group IV and group IV alloy-based amorphous semiconductor layers suitable for the photovoltaic device of the present invention, a gasizable compound containing silicon atoms and a germanium atom can be used. Containing gasifiable compounds,
A gasizable compound containing a carbon atom, a compound containing a nitrogen atom which can be pre-gasified, a gasizable compound containing an oxygen atom, and the like, and a mixed gas of the compound can be produced.

As a gaseous compound containing a silicon atom, a chain or cyclic silane compound is used. Specifically, for example, SiH ₄ , Si ₂ H ₆ , Si
_{F 4, SiFH 3, SiF 2} H 2, SiF 3 H, Si 3 H 8,
SiD ₄ , SiHD ₃ , SiH ₂ D ₂ , SiH ₃ D, SiF
D ₃ , SiF ₂ D ₂ , SiD ₃ H, Si ₂ D ₃ H ₃ , (Si
F ₂ ) ₅ , (SiF ₂ ) ₆ , (SiF ₂ ) ₄ , Si ₂ F ₆ , Si
_{3 F 8, Si 2 H 2} F 4, Si 2 H 3 F 3, SiCl 4, (Si
Cl ₂ ) ₅ , SiBr ₄ , (SiBr ₂ ) ₅ , Si ₂ Cl ₆ ,
SiHCl ₃ , SiH ₂ Br ₂ , SiH ₂ Cl ₂ , Si ₂ Cl
₃ which may or easily gasified gas conditions such as F ₃ and the like.

Specifically, a gas containing a germanium atom
The compound which can be converted to is GeH_Four, GeD_Four, GeF_Four,
GeFH_Three, GeF_TwoH_Two, GeF_ThreeH, GeHD_Three, Ge
H_TwoD _Two, GeH_ThreeD, Ge_TwoH₆, Ge_TwoD₆Etc.
You. Specifically, a gasizable compound containing a carbon atom and
Then CH_Four, CD_Four, C _nH_{2n + 2}(N is an integer), C_nH
_2n(N is an integer), C_TwoH_Two, C₆H₆, CO_Two, CO etc.
I can do it.

As the nitrogen-containing gas, N ₂ , NH ₃ , N
D ₃ , NO, NO ₂ and N ₂ O are mentioned. O ₂ , CO, CO ₂ , NO, NO ₂ , N ₂ O, CH
₃ CH ₂ OH, CH ₃ OH, etc. In addition, as a substance introduced into the p-type layer or the n-type layer for controlling valence electrons, there may be mentioned a Group III element and a Group V atom of the periodic table.

As a starting material for introducing a group III atom effectively, specifically, for introducing a boron atom, B ₂ H ₆ , B ₄ H ₁₀ , B ₅ H ₉ , B ₅ H ₁₁ , B _{6
H 10, B 6 H 12,} B 6 H 14 hydride such as boron, BF _3, B
Examples thereof include halogenated boron such as Cl ₃ .
In addition, AlCl ₃ , GaCl ₃ , InCl ₃ , TIC
l ₃ and the like can also be mentioned. Particularly, B ₂ H ₆ and BF ₃ are suitable. As a starting material for introducing a group V atom, it is effective to specifically use hydrogenation of PH ₃ and P ₂ H ₄ for introducing a phosphorus atom. Phosphorus, PH ₄ I, PF ₃ , PF ₅ , PCl ₃ , PC
phosphorus halides such as l ₅ , PBr ₃ , PBr ₅ , and PI ₃ . In addition, AsH ₃ , AsF ₃ , AsCl ₃ , As
Br ₃ , AsF ₅ , SbH ₃ , SbF ₃ , SbF ₅ , SbC
l ₃ , SbCl ₅ , BiH ₃ , BiCl ₃ , BiBr _{3 and the} like can also be mentioned. Particularly, PH ₃ and PF ₃ are suitable.

The compounds capable of being gasified are H ₂ , H
The gas may be appropriately diluted with a gas such as e, Ne, Ar, Xe, or Kr and introduced into the deposition chamber. In particular, microcrystalline semiconductors and a-Si
In the case of depositing a layer having a small light absorption such as C: H or a wide band gap, the source gas is diluted 2 to 100 times with hydrogen gas, and a relatively high microwave power or RF power is introduced. Is preferred.

(Transparent Electrode) The transparent electrode desirably has a light transmittance of 85% or more in order to efficiently absorb light from the sun, a white fluorescent lamp, or the like into each semiconductor layer.
Further, it is desirable that the sheet resistance is 100Ω or less so that the resistance of the output of the photovoltaic element does not become a resistance component. As a material having such properties, S
nO ₂ , In ₂ O ₃ , ZnO, CdO, Cd ₂ SnO ₄ , I
Metal oxides such as TO (In ₂ O ₃ + SnO ₂ );
Examples of the metal thin film include a metal such as u, Al, and Cu that is formed to be extremely thin and translucent. The transparent electrode is laminated on the p-type layer or the n-type layer in the photovoltaic element, forms the photovoltaic element on the translucent support, and irradiates light from the translucent support side. Is laminated on a support, it is necessary to select one having good mutual adhesion. Further, it is preferable that the transparent electrode is deposited to a thickness that meets the antireflection conditions. As a method for producing a transparent electrode, resistance heating evaporation, electron beam heating evaporation,
A sputtering method, a spray method, or the like can be used, and is appropriately selected as desired.

(Current Collecting Electrode) The current collecting electrode of the photovoltaic element subjected to the hydrogen plasma treatment of the present invention may be formed by screen printing silver paste, or may be made of Cr, Ag, Au,
It may be formed by vacuum evaporation using a mask of Cu, Ni, Δo, Al or the like. Alternatively, carbon or Ag powder may be attached to a metal wire such as Cu, Au, Ag, or Al together with a resin and attached to the surface of the photovoltaic element to form a current collecting electrode.

When a photovoltaic device of a desired output voltage and output current is manufactured using the photovoltaic device of the present invention, the photovoltaic devices of the present invention are connected in series or in parallel. A protective layer is formed on the front and back surfaces, and output output electrodes and the like are attached. When the photovoltaic elements of the present invention are connected in series, a diode for preventing backflow may be incorporated.

[0083]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for forming a photovoltaic element of the present invention will be described in detail for a solar cell made of a non-single-crystal silicon-based semiconductor material, but the present invention is not limited thereto. (Example 1) The solar cell of FIG. 1 was manufactured using the deposition apparatus shown in FIG. First, a substrate was manufactured. Thickness 0.5
mm, 50 × 50 mm ² stainless steel support (10 mm
0) was ultrasonically washed with acetone and isopropanol and dried with warm air.

Using a sputtering method, a 0.3 μm thick Ag layer was formed on the surface of a stainless steel support (100) at room temperature.
Light reflecting layer (101) and a layer thickness of 1.0 at 350 ° C.
A μm ZnO reflection enhancement layer (102) was formed, and the fabrication of the substrate was completed. Next, the deposition apparatus 400 can perform both the MWPCVD method and the RFPCVD method. Using this, each semiconductor layer was formed on the reflection increasing layer.

A raw material gas cylinder (not shown) is provided in the deposition apparatus.
It is connected through the inlet pipe. Raw gas cylinder Yes
The deviation is also purified to ultra-high purity,_FourGas bon
Ba, SiF_FourGas cylinder, CH_FourGas cylinder, GeH_FourMoth
Bomb, GeF_FourGas cylinder, Si_TwoH₆Gas cylinders,
PH_Three/ H_Two(Dilution: 1000 ppm) Gas cylinder, B
_TwoH₆/ H_Two(Dilution: 2000 ppm, 1%, 10%)
Gas cylinder, BF_Three/ H_Two(Dilution 2000ppm, 1
%, 10%) gas cylinder, H_TwoGas cylinder, He gas bottle
Nmbe, SiCl_TwoH_TwoGas cylinder, SiH_Four/ H_Two(Dilution
(Degree: 1000 ppm) Gas was connected.

Next, the substrate 490 on which the reflection layer 101 and the reflection enhancement layer 102 are formed is placed on the substrate transfer rail 413 in the load chamber 401, and the inside of the load chamber 401 is pressurized by a vacuum exhaust pump (not shown). Is about 1
The chamber was evacuated to ^10-5 Torr. Next, the gate valve 406 was opened and transported into the transport chamber 402 and the deposition chamber 417, which were previously evacuated by a vacuum pump (not shown). The back surface of the substrate 490 was heated by being brought into close contact with a heater 410 for heating the substrate, and the inside of the deposition chamber 417 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

The preparation for film formation was completed as described above.
Thereafter, an RF n-type layer 103 made of μc-Si was formed.
To form an RF n-type layer made of μc-Si, H_TwoMoth
Through the gas introduction pipe 429 into the deposition chamber 417.
And introduced, H_TwoSo that the gas flow rate is 180sccm
Open the valves 441, 431, and 430, and
It was adjusted with the Troller 436. Inside the deposition chamber 417
(Not shown) so that the pressure becomes 1.10 Torr.
It was adjusted with a reactance valve. When the temperature of the substrate 490 is 370
Set the substrate heating heater 410 to
When the plate temperature is stabilized, the SiH_FourGas, PH_Three/ H_Two
The gas is supplied to the deposition chamber 417 by the valves 443 and 43.
3, 444 and 434 are operated to pass through the gas introduction pipe 429.
Introduced. At this time, SiH _FourGas flow rate is 1.5scc
m, H_TwoGas flow rate 110sccm, PH_Three/ H_TwoGas flow
Mass flow control so that the volume is 200 sccm
438, 436, 439
Adjust the pressure in 417 to 1.15 Torr.
Was. The power of the RF power supply 422 is set to 0.05 W / cm^ThreeSet to
Then, RF power is introduced into the plasma forming cup 420,
Glow discharge is generated, and the formation of an RF n-type layer on the substrate is started.
When an RF n-type layer having a thickness of 20 nm is formed, R
F power is turned off, glow discharge is stopped, and the RF n-type layer 103 is turned off.
Finished the formation. SiH into the deposition chamber 417_Four
Gas, PH_Three/ H_TwoThe flow of H into the deposition chamber for 5 minutes.
_TwoAfter continuing the gas flow, H_TwoStop the inflow of
And 1 × 10^-FiveEvacuate to Torr
Was.

Next, an n / i buffer layer 151 made of a-Si was formed by RFPCVD. First, the transfer chamber 403 and the i-type layer deposition chamber 41 evacuated by a vacuum pump (not shown) in advance.
8, the gate valve 407 was opened, and the substrate 490 was transported. The back surface of the substrate 490 was heated by being brought into close contact with a heater 411 for heating the substrate, and the inside of the i-type layer deposition chamber 418 was evacuated by a vacuum exhaust pump (not shown) until the pressure reached about 1 × 10 ⁻⁵ Torr.

In order to form the n / i buffer layer 151, the substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 360 ° C., and when the base plate is sufficiently heated, the valves 464, 454, 450, 463 and 453 are gradually opened, and Si ₂ H ₆ gas and H ₂ gas are introduced into the gas introduction pipe 4.
49, and flowed into the i-type layer deposition chamber 418. In this case, Si ₂ H ₆ gas flow rate is 3.5 sccm, H ₂
The mass flow controllers 459 and 458 adjusted the gas flow rate to 100 sccm. The opening of the conductance valve (not shown) was adjusted so that the pressure in the i-type layer deposition chamber 418 became 0.8 Torr. Next, a high frequency (hereinafter abbreviated as “RF”) power supply 42
4 was set to 0.06 W / cm ³ , and applied to the bias rod 428 to generate glow discharge. By opening the shutter 427, the production of the n / i buffer layer was started on the RF n-type layer, and the layer thickness was 10 nm. When the n / i buffer layer was manufactured, the RF glow discharge was stopped, the output of the RF power supply 424 was turned off, and the manufacture of the n / i buffer layer 151 was completed. The valves 464 and 454 are closed, and the i-type layer deposition chamber 4 is closed.
Stopping the flow of Si ₂ H ₆ gas into the 18, after continued to flow H ₂ gas to 2 minutes i-type layer deposition chamber 418, closing the valve 453,450, i-type layer deposition chamber 41
8 and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Next, the MWi type layer 10 made of a-SiGe
4 was formed by the MWPCVD method. To manufacture the MWi-type layer, the substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 370 ° C., and when the substrate is sufficiently heated, the valves 461, 451, 450, 462,
452, 463, and 453 were gradually opened, and SiH ₄ gas, GeH ₄ gas, and H ₂ gas were flowed into the i-type layer deposition chamber 418 through the gas introduction pipe 449.

At this time, the flow rate of the SiH ₄ gas is 38 scc.
m, GeH ₄ gas flow rate is 39 sccm, H ₂ gas flow rate is 1
The mass flow controllers 456, 457, and 458 adjusted the pressure to 65 sccm. The opening of the conductance valve (not shown) was adjusted so that the pressure in the i-type layer deposition chamber 418 became 6 mTorr. Next, a high frequency (hereinafter abbreviated as “RF”) power supply 424 was set to 0.70 W / cm ³ and applied to the bias rod 428. Thereafter, the power of the MW power supply (not shown) was reduced to 0.28 W /
cm ³ , waveguide 426 and microwave introduction window 4
25, MW power is introduced into the i-type layer deposition chamber 418 to generate a glow discharge, and the shutter 427 is opened to start forming an MWi-type layer on the n / i buffer layer. When the mold layer was manufactured, the MW glow discharge was stopped, the output of the bias power supply 424 was turned off, and the manufacture of the MWi type layer 204 was completed. Valve 451,
452 is closed and the S is introduced into the i-type layer deposition chamber 418.
iH4 gas, stopping the flow of GeH ₄ gas, after continued to flow H ₂ gas to 2 minutes i-type layer deposition chamber 418,
The valves 453 and 450 are closed, and the i-type layer deposition chamber 4 is closed.
The inside of 18 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Next, ap / i buffer layer 161 made of a-Si was formed by RFPCVD. To form the p / i buffer layer 161, the temperature of the substrate
The substrate heating heater 411 is set at 30 ° C., and when the substrate is sufficiently heated, the valves 464 and 45 are set.
4, 450, 463 and 453 are gradually opened, and Si ₂ H ₆
Gas and H ₂ gas were introduced into the i-type layer deposition chamber 418 through the gas introduction pipe 449. At this time, the mass flow controllers 459 and 45 were set so that the flow rate of the Si ₂ H ₆ gas was 3 sccm and the flow rate of the H ₂ gas was 80 sccm.
Adjusted at 8. The opening of the conductance valve (not shown) was adjusted so that the pressure in the i-type layer deposition chamber 418 became 0.8 Torr. Next, the RF power source 424 is set to 0.07 W / cm ³ , and is applied to the bias bar 428 to generate a glow discharge. By opening the shutter 427, the p / i buffer layer is formed on the MWi-type layer. Then, when a 20 nm-thick p / i buffer layer was formed, the RF glow discharge was stopped, the output of the RF power supply 424 was turned off, and the formation of the p / i buffer layer 161 was completed. The valves 464 and 454 are closed, and the i-type layer deposition chamber 418 is closed.
After stopping the flow of the Si ₂ H ₆ gas into the inside, the H ₂ gas is kept flowing into the i-type layer deposition chamber 418 for 2 minutes, then the valves 453 and 450 are closed, and the i-type layer deposition chamber 418 and the gas pipes are closed. Was evacuated to 1 × 10 ⁻⁵ Torr.

Next, a hydrogen plasma treatment containing trace amounts of Group III elements according to the present invention was performed. In order to carry out the hydrogen plasma treatment containing a trace amount of group III element according to the present invention, a B ₂ H ₆ / H ₂ (dilution: 10%) gas is used as a group III element-containing gas, a SiH ₄ gas is used as a silicon atom-containing gas, and a H ₂ gas is used. ₂ gas is introduced into the deposition chamber 418 through the gas introduction pipe 449, and the valves 463 and 4 are adjusted so that the H ₂ gas flow rate becomes 1500 sccm.
Open 53, 450 and open the mass flow controller 458
Was adjusted. The valve 46 is set so that the group III element-containing gas B ₂ H ₆ / H ₂ gas becomes 0.5% of the total H ₂ gas flow rate.
8, 466 were opened and adjusted by the mass flow controller 467. Silicon atom-containing gas, SiH ₄ gas is all H ₂
The valve 46 is set to be 0.01% with respect to the gas flow rate.
1, 451 were opened and adjusted by the mass flow controller 456. The pressure in the deposition chamber 418 is 0.7 Torr
r was adjusted by a conductance valve (not shown). The substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 200 ° C. When the substrate temperature is stabilized, the power of the RF power supply 424 is set to 0.06 W / cm ³ , and the RF power is supplied to the bias rod 428. Applied. A glow discharge is generated in the deposition chamber 418 to generate the shutter 42.
7 was opened, and a hydrogen plasma treatment containing trace amounts of Group III elements of the present invention was performed for 3 minutes. Thereafter, the RF power is turned off to stop the glow discharge, and B ₂ H ₆ / H ₂ into the deposition chamber 418.
(Dilution: 10%) Stop the flow of gas and SiH ₄ gas,
After continuously flowing the H ₂ gas into the deposition chamber 418 for 3 minutes, the flow of the H ₂ gas is stopped, and the deposition chamber 418 is stopped.
The inside and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Next, the RFp type layer 105 made of a-SiC
Was formed. In order to form the RFp-type layer 105 made of a-SiC, the gate valve 408 is opened into the transfer chamber 404 and the P-type layer deposition chamber 419 that have been evacuated in advance by a vacuum pump (not shown) to remove the substrate 490. Conveyed. The back surface of the substrate 490 is brought into close contact with the substrate heating heater 412 and heated, and the pressure in the p-type layer deposition chamber 419 is reduced to about 1 × by a vacuum exhaust pump (not shown).
The chamber was evacuated to 10 ^-5 Torr.

The temperature of the substrate 490 is set to 200 ° C.
Set the substrate heating heater 412 to keep the substrate temperature stable.
By the way, H_TwoGas, SiH_Four/ H_TwoGas, B_TwoH₆/ H_Two
Gas, CH_FourThe gas is introduced into the deposition chamber 419 by the valve 4.
81, 471, 470, 482, 472, 483, 47
Operate 3, 484, 474 through gas introduction pipe 469
Introduced. At this time, H_TwoGas flow rate is 90scm, Si
H_Four/ H_TwoGas flow rate 1sccm, B_TwoH₆/ H_TwoGas flow
Is 10 sccm, CH_FourGas flow becomes 0.3sccm
Like the mass flow controllers 476, 477, 47
8 and 479, the pressure in the deposition chamber 419 is
The conductance bar (not shown) is set to 1.3 Torr.
The lube opening was adjusted. The power of the RF power supply 423 is set to 0.0
9W / cm ^ThreeTo the plasma forming cup 421
RF power is introduced to generate glow discharge, and p / i battery
The formation of an RFp type layer on the far layer is started, and the layer thickness is 10 nm.
When the RF p-type layer is formed, the RF power is turned off, and the
The low discharge was stopped, and the formation of the RFp type layer 105 was completed. Bal
472, 482, 473, 483, 474, 484
Close and place SiH into p-type layer deposition chamber 419_Four/ H_Two
Gas, B_TwoH₆/ H_TwoGas, CH_FourStop gas flow for 3 minutes
During the time, H is introduced into the p-type layer deposition chamber 419._TwoContinue flowing gas
After firing, the valves 471, 481, and 470 are closed and H_Two
Of p-type layer deposition chamber 419 and gas
1 × 10 inside the piping^-FiveEvacuated to Torr.

Next, the gate valve 409 is opened into the unload chamber 405 evacuated by a vacuum pump (not shown), and the substrate 490 is transported.
5 leaked. Next, as the transparent conductive layer 112, ITO having a thickness of 70 nm was vacuum-deposited on the RFp-type layer 105 by a vacuum evaporation method.

Next, a mask having a comb-shaped hole is placed on the transparent conductive layer 112, and Cr (40 nm) / Ag (1000 n
m) / Combined current collector electrode 113 made of Cr (40 nm)
Was vacuum deposited by a vacuum deposition method. Thus, the production of the solar cell has been completed. This solar cell is called (SC Ex. 1),
Hydrogen plasma treatment conditions containing trace amounts of Group III elements of the present invention,
RFn type layer, RFn / i buffer layer, MWi type layer, R
Table 1 shows the conditions for forming the Fp / i buffer layer and the RFp type layer.
(1), shown in 1 (2).

<Comparative Example 1> A solar cell (SC ratio 1) was manufactured under the same conditions as in Example 1 except that the hydrogen plasma treatment containing trace amounts of Group III elements according to the present invention was not performed. Eight solar cells (SC Ex. 1) and (SC ratio 1) were manufactured, each having eight photoelectric conversion efficiencies (photovoltaic power / incident optical power), vibration degradation, light degradation, and high temperature and high humidity when bias voltage was applied. Vibration degradation and light degradation in the environment were measured.

The initial photoelectric conversion efficiency can be obtained by installing the produced solar cell under AM1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristics. As a result of the measurement, for (SC ratio 1), the fill factor (FF) of the initial photoelectric conversion efficiency of (SC actual 1) and the series resistance (Rs)
And the characteristic unevenness was as follows. Fill factor Series resistance Characteristic unevenness (SC actual 1) 1.18 times 0.91 times 0.88 times For the measurement of vibration deterioration, a solar cell whose initial photoelectric conversion efficiency was measured in advance was a humidity of 57% and a temperature of 25 ° C. In a dark place with a vibration frequency of 60 Hz and an amplitude of 0.1 mm
AM1.5 (100 mW / cm ² ) after adding for 0 hours
The measurement was performed based on the rate of decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after vibration degradation test / initial photoelectric conversion efficiency).

The photodegradation was measured by placing a solar cell, whose initial photoelectric conversion efficiency was measured in advance, in an environment of a humidity of 57% and a temperature of 25 ° C., and was exposed to AM1.5 (100 mW / cm ² ) light for 550 hours. After irradiation, AM1.5 (100 mW / c
m ² ) The rate of decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after light degradation test / initial photoelectric conversion efficiency). As a result of the measurement, the rate of decrease in photoelectric conversion efficiency after light deterioration (SC ratio 1) and the rate of decrease in photoelectric conversion efficiency after vibration deterioration with respect to (SC actual 1) were as follows.

[0101] Vibration degradation and light degradation in a high temperature and high humidity environment at the time of bias application were measured. Two solar cells whose initial photoelectric conversion efficiency was measured in advance were placed in a dark place at a humidity of 92% and a temperature of 85 ° C., and 0.71 V was applied as a forward bias voltage. The above-mentioned vibration was applied to one of the solar cells to measure the vibration degradation, and the other solar cell was subjected to AM1.
The sample was irradiated with the light of No. 5 to measure photodegradation. As a result of the measurement, the reduction rate of the photoelectric conversion efficiency after the vibration deterioration of (SC ratio 1) and the reduction rate of the photoelectric conversion efficiency after the light deterioration of (SC ratio 1) are as follows with respect to (SC actual 1).

[0102] The state of delamination was observed using an optical microscope. In (SC Ex. 1), no delamination was observed, but in (SC ratio 1), delamination was slightly observed. As described above, the solar cell (SC Ex. 1) of the present invention has a better fill factor, series resistance, characteristic unevenness, light deterioration characteristic, adhesion, and so on than the conventional solar cell (SC ratio 1) in the photoelectric conversion efficiency of the solar cell. It was found that it had more excellent properties in durability.

Example 2 Using the deposition apparatus shown in FIG. 4, the tandem solar cell shown in FIG. 2 was manufactured. Reflection layer 201 and reflection enhancement layer 20 prepared by the same method as in Example 1.
2 is formed in the load chamber 40.
The load chamber 401 was evacuated by a vacuum evacuation pump (not shown) until the pressure reached about 1 × 10 ⁻⁵ Torr.

Next, the gate valve 406 was opened and transferred into the transfer chamber 402 and the deposition chamber 417, which were previously evacuated by a vacuum pump (not shown). The back surface of the substrate 490 was heated by being brought into close contact with a heater 410 for heating the substrate, and the inside of the deposition chamber 417 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

Preparation for film formation was completed as described above.
Thereafter, an RF n-type layer 203 made of μc-Si was formed.
To form an RF n-type layer made of μc-Si, H_TwoMoth
Through the gas introduction pipe 429 into the deposition chamber 417.
And introduced, H_TwoSo that the gas flow rate is 300sccm
Open the valves 441, 431, and 430, and
It was adjusted with the Troller 436. Inside the deposition chamber 417
(Not shown) so that the pressure becomes 1.1 Torr.
Adjusted with a lance valve. The temperature of the substrate 490 is 380 ° C.
The heater 410 for the base slope heating is set so that
When the temperature stabilizes, the SiH _FourGas, PH_Three/ H_TwoMoth
Valves 443 and 433 in the deposition chamber 417.
Operate 444 and 434 to guide through gas introduction pipe 429.
Entered. At this time, SiH_FourGas flow rate is 1.5sccm,
H_TwoGas flow rate 90 sccm, PH_Three/ H_TwoGas flow is 2
Mass flow controller 4 so that it becomes 00sccm
38, 436 and 439, the deposition chamber 417
The internal pressure was adjusted to be 1.1 Torr. RF
The power of the power supply 422 is 0.05 W / cm^ThreeSet to
RF power is introduced into the cup 420 for forming
To generate an RF n-type layer on the substrate,
When the RF n-type layer having a thickness of 20 nm is formed, the RF power supply is turned on.
Cut off the glow discharge to stop the formation of the RF n-type layer 203.
finished. SiH into the deposition chamber 417_FourGas, P
H_Three/ H_TwoThe flow of H into the deposition chamber for 4 minutes._TwoGas
After continuing to flow, H_TwoStop the inflow of
1 × 10 inside the piping^-FiveEvacuated to Torr.

Next, an n / i buffer layer 251 made of a-Si was formed by RFPCVD. First, the transfer chamber 403 and the i-type layer deposition chamber 41 evacuated by a vacuum pump (not shown) in advance.
8, the gate valve 407 was opened, and the substrate 490 was transported. The back surface of the substrate 490 was heated by being brought into close contact with a heater 411 for heating the substrate, and the inside of the i-type layer deposition chamber 418 was evacuated by a vacuum exhaust pump (not shown) until the pressure reached about 1 × 10 ⁻⁵ Torr.

To form the n / i buffer layer 251
Heats the substrate so that the temperature of the substrate 490 becomes 360 ° C.
Heater 411 is set and the board is sufficiently heated.
Filter valves 464, 454, 450, 463, 453
Open gradually, Si_TwoH₆Gas, H_TwoGas inlet pipe 4
49 into the i-type layer deposition chamber 418
Was. At this time, Si_TwoH₆Gas flow rate 2.5 sccm, H_Two
Each mass flow so that the gas flow rate is 90 sccm
The adjustment was performed by the controllers 459 and 458. i-type layer deposition
The pressure inside the chamber 418 will be 0.8 Torr
Thus, the opening of the conductance valve (not shown) was adjusted.
Next, the RF power supply 424 is set to 0.08 W / cm ^ThreeSet to
The glow discharge is applied to the bias rod 428 to generate a glow discharge.
By opening the shutter 427, the n / i barrier
Production of a buffer layer is started, and a 10 nm thick n / i buffer
When the fur layer was formed, the RF glow discharge was stopped.
The output of the F power supply 424 is turned off, and the n / i buffer layer 251 is turned off.
Finished. Close the valves 464 and 454,
Si into layer deposition chamber 418_TwoH₆Stop gas flow
Into the i-type layer deposition chamber 418 for 2 minutes._TwoGas
After continuing the flow, the valves 453 and 450 are closed, and the i-type layer
1 × 10 in the deposition chamber 418 and gas pipe^-Five
Evacuated to Torr.

Next, the MWi type layer 20 made of a-SiGe
4 was formed by the MWPCVD method. To manufacture the MWi-type layer, the substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 380 ° C., and when the substrate is sufficiently heated, the valves 461, 451, 450, 462,
452, 463, and 453 were gradually opened, and SiH ₄ gas, GeH ₄ gas, and H ₂ gas were flowed into the i-type layer deposition chamber 418 through the gas introduction pipe 449.

At this time, the flow rate of the SiH ₄ gas is 45 scc.
m, GeH ₄ gas flow rate is 43 sccm, H ₂ gas flow rate is 1
The mass flow controllers 456, 457, and 458 adjusted the flow rate to 75 sccm. The opening of the conductance valve (not shown) was adjusted so that the pressure in the i-type layer deposition chamber 418 became 5 mTorr. Next, the RF power source 424 was set at 0.65 W / cm ³ and applied to the bias bar 428. Thereafter, the power of a MW power supply (not shown) is set to 0.25 W / cm ³ , and MW power is introduced into the i-type layer deposition chamber 418 through the waveguide 426 and the microwave introduction window 425 to generate glow discharge.
By opening the shutter 427, the production of the MWi-type layer on the n / i buffer layer is started. When the i-type layer having a thickness of 0.15 μm is produced, the MW glow discharge is stopped, and the output of the bias power supply 424 is turned off. The fabrication of the mold layer 204 has been completed. The valves 451 and 452 are closed to stop the flow of the SiH ₄ gas and the GeH ₄ gas into the i-type layer deposition chamber 418, and the H ₂ gas is continuously flown into the i-type layer deposition chamber 418 for 2 minutes. , 450 are closed, and the inside of the i-type layer deposition chamber 418 and the
^The chamber was evacuated to ^-5 Torr.

Next, ap / i buffer layer 261 made of a-Si was formed by RFPCVD. To form the p / i buffer layer 261, the temperature of the substrate
The substrate heating heater 411 is set at 50 ° C., and when the substrate is sufficiently heated, the valves 464 and 45 are set.
4, 450, 463 and 453 are gradually opened, and Si ₂ H ₆
Gas and H ₂ gas were introduced into the i-type layer deposition chamber 418 through the gas introduction pipe 449. At this time, the mass flow controllers 459 and 45 were set so that the flow rate of the Si ₂ H ₆ gas was 3 sccm and the flow rate of the H ₂ gas was 80 sccm.
Adjusted at 8. The opening of the conductance valve (not shown) was adjusted so that the pressure in the i-type layer deposition chamber 418 became 0.7 Torr. Next, the RF power source 424 is set to 0.07 W / cm ³ , applied to the bias bar 428 to generate glow discharge, and the shutter 427 is opened to form the p / i buffer layer 261 on the MWi-type layer. Starting, when a 20 nm-thick p / i buffer layer was formed, the RF glow discharge was stopped, the output of the RF power supply 424 was turned off, and the formation of the p / i buffer layer 261 was completed.
The valves 464 and 454 are closed to stop the flow of the Si ₂ H ₆ gas into the i-type layer deposition chamber 418, and the H ₂ gas is continuously flown into the i-type layer deposition chamber 418 for 2 minutes.
The valves 453 and 450 are closed, and the i-type layer deposition chamber 4 is closed.
The inside of 18 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Next, a hydrogen plasma treatment containing trace amounts of Group III elements according to the present invention was performed under the conditions shown in Table 2 (1). In order to carry out the hydrogen plasma treatment containing a trace amount of group III element according to the present invention, a BF ₃ / H ₂ (dilution: 1%) gas is used as a group III element-containing gas, and a Si ₂ H ₆ gas is used as a silicon atom-containing gas. , H ₂
The gas was introduced into the deposition chamber 418 through the gas introduction pipe 449, and the valves 463, 453, and 450 were opened so that the flow rate of the H ₂ gas became 1000 sccm, and the gas was adjusted by the mass flow controller 458. The valves 468 and 466 were opened and the mass flow controller 467 was adjusted so that the group III element-containing gas BF ₃ / H ₂ gas became 0.4% of the total H ₂ gas flow rate. Silicon atom containing gas,
The valves 464 and 454 were opened to adjust the mass flow controller 459 so that Si ₂ H ₆ became 0.05% of the total H ₂ gas flow rate. The pressure inside the deposition chamber 418 was adjusted to 0.018 Torr by a conductance valve (not shown). The substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 250 ° C. When the substrate temperature becomes stable, the VHF power of a VHF power supply (not shown) is set to 0.08 W / cm ³ , and the bias rod 428 is set. And a glow discharge is generated in the deposition chamber 418 to open the shutter 427 for 4 minutes.
A group-element-containing hydrogen plasma treatment was performed. Thereafter, the VHF power supply is turned off, the glow discharge is stopped, and the deposition chamber 418 is turned off.
Stopping the flow of _{BF 3 / H 2, Si 2} H 6 gas to the inner, 4 minutes, after continued to flow H ₂ gas into the deposition chamber 418, stopping the inflow of H ₂ gas, the deposition chamber 418 and the gas The inside of the pipe was evacuated to 1 × 10 ⁻⁵ Torr.

Next, the RFp type layer 205 made of a-SiC
In order to form the substrate, the gate valve 408 was opened and the substrate 490 was transferred into the transfer chamber 404 and the p-type layer deposition chamber 419 that were previously evacuated by a vacuum pump (not shown). The back surface of the substrate 490 was heated by being brought into close contact with a heater 412 for heating the substrate, and the inside of the p-type layer deposition chamber 419 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

The temperature of the substrate 490 is set to 250 ° C.
Set the substrate heating heater 412 to keep the substrate temperature stable.
By the way, H_TwoGas, SiH_Four/ H_TwoGas, B_TwoH₆/ H_Two
Gas, CH_FourThe gas is introduced into the deposition chamber 419 by the valve 4.
81, 471, 470, 482, 472, 483, 47
Operate 3, 484, 474 through gas introduction pipe 469
Introduced. At this time, H_TwoGas flow rate 60scm, Si
H_Four/ H_TwoGas flow rate 2sccm, B_TwoH₆/ H_TwoGas flow
Is 10 sccm, CH_FourGas flow becomes 0.3sccm
Like the mass flow controllers 476, 477, 47
8 and 479, the pressure in the deposition chamber 419 is
A conductance bar (not shown) is set to 1.7 Torr.
The lube opening was adjusted. The power of the RF power supply 423 is set to 0.0
7W / cm ^ThreeTo the plasma forming cup 421
RF power is introduced to generate glow discharge, and p / i battery
The formation of an RFp type layer on the far layer is started, and the layer thickness is 10 nm.
When the RF p-type layer is formed, the RF power is turned off, and the
The low discharge was stopped, and the formation of the RFp type layer 205 was completed. Ba
Lubes 472, 482, 473, 483, 474, 484
Is closed and the SiH is introduced into the p-type layer deposition chamber 419._Four/
H_TwoGas, B_TwoH₆/ H_TwoGas, CH_FourStop the gas flow,
3 minutes into the p-type layer deposition chamber 419_TwoFlowing gas
And then close valves 471, 481 and 470
H_TwoOf the p-type layer deposition chamber 419 and
1 × 10 inside gas pipe^-FiveEvacuated to Torr.

Next, an RF n-type layer 206 made of μc-Si
In order to form the substrate, the substrate was transported into the transport chamber 402 and the deposition chamber 417 by opening the gate valves 408 and 407 through the transport chamber 403 evacuated by a vacuum pump (not shown) in advance. Substrate 4
The back surface of the substrate 90 was heated by being brought into close contact with a heater 410 for heating a substrate, and the inside of the deposition chamber 417 was evacuated by a vacuum exhaust pump (not shown) until the pressure reached about 1 × 10 ⁻⁵ Torr.

Form RF n-Type Layer of μc-Si
H_TwoGas is introduced into the deposition chamber 417
429, introduced by H_TwoGas flow rate is 200sccm
Open the valves 441, 431 and 430 so that
It was adjusted by the flow controller 436. Sedimentary chan
Unnecessary so that the pressure in the bar 417 becomes 1.1 Torr
It was adjusted with the indicated conductance valve. Temperature of substrate 490
The substrate heating heater 410 is set to a temperature of 250 ° C.
When the substrate temperature is stabilized,_Fourgas,
PH_Three/ H_TwoThe gas is introduced into the deposition chamber 417 by the valve 44.
3, 433, 444, and 434 are operated to operate the gas introduction pipe 42.
9 introduced. At this time, SiH _FourGas flow is 2s
ccm, H_TwoGas flow rate 75 sccm, PH_Three/ H_Twogas
Mass flow control so that the flow rate is 250 sccm
438, 436, 439
The pressure inside -417 was adjusted to be 1.1 Torr.
Was. The power of the RF power supply 422 is set to 0.04 W / cm^ThreeSet to
Then, RF power is introduced into the plasma forming cup 420,
A glow discharge is generated to form an RFn-type layer on the RFp-type layer.
Started to form an RF n-type layer with a thickness of 10 nm.
Turn off the RF power at the filter to stop the glow discharge.
The formation of 206 was completed. S in the deposition chamber 417
iH_FourGas, PH_Three/ H_TwoStop the inflow of water for 2 minutes in the deposition chamber
H inside_TwoAfter continuing the gas flow, H_TwoStops inflow of water and accumulates
1 × 10 in the room and gas pipe^-FiveEvacuate to Torr
I noticed.

Next, an n / i buffer layer 252 made of a-SiC was formed by RFPCVD. First, the transfer chamber 403 and the i-type layer deposition chamber 4 evacuated by a vacuum pump (not shown) in advance.
18, the gate valve 407 was opened and the substrate 490 was transported. The back surface of the substrate 490 is heated by bringing the back surface of the substrate 490 into close contact with the heater 411 for heating the substrate, and the pressure in the i-type layer deposition chamber 418 is about 1 × 10 ⁻⁵ Torr by a vacuum pump (not shown).
The chamber was evacuated until.

To form the n / i buffer layer 252, the substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 250 ° C., and when the substrate is sufficiently heated, the valves 464, 454, 450, and 463 are set. , 453,
465 and 455 were gradually opened, and Si ₂ H ₆ gas, H ₂ gas, and CH ₄ gas were caused to flow into the i-type layer deposition chamber 418 through the gas introduction pipe 449. At this time, the flow rate of the Si ₂ H ₆ gas was 0.4 sccm, and the flow rate of the H ₂ gas was 85 scc.
The mass flow controllers 459, 458, and 460 adjusted the flow rates of m and CH ₄ gas to 0.2 sccm.

The pressure in the i-type layer deposition chamber 418 is
The opening of the conductance valve (not shown) was adjusted to 1.1 Torr. Next, the RF power supply 424 is set to 0.0
It is set to 6 W / cm ³ and applied to the bias rod 428 to generate a glow discharge. By opening the shutter 427, the production of an n / i buffer layer on the RF n-type layer is started. When the buffer layer was prepared, R
F glow discharge is stopped, the output of the RF power supply 424 is turned off, and n
The production of the / i buffer layer 252 was completed. Valve 46
4, 454, 465 and 455 are closed to stop the flow of the Si ₂ H ₆ gas and the CH ₄ gas into the i-type layer deposition chamber 418, and the H ₂ gas continues to flow into the i-type layer deposition chamber 418 for 2 minutes. After that, the valves 453 and 450 are closed, and the inside of the i-type layer
^The chamber was evacuated to ^-5 Torr.

Next, the RFi type layer 207 made of a-Si
It was formed by the RFPCVD method. Fabricate RFi-type layer
In order for the temperature of the substrate 490 to be 200 ° C.
The heating heater 411 was set, and the substrate was sufficiently heated.
By the way, valves 464, 454, 450, 463, 45
3 is gradually opened and Si_TwoH₆Gas, H_TwoIntroduce gas
Flow into i-type layer deposition chamber 418 through tube 449
I let it. At this time, Si _TwoH₆Gas flow rate of 2.8 sccm,
H_TwoSet each mask so that the gas flow rate is 80 sccm.
The adjustment was made with the low controllers 459 and 458. i-type layer
The pressure in the deposition chamber 418 is 0.5 Torr.
Adjust the opening of the conductance valve (not shown)
Was. Next, the RF power supply 424 is set to 0.07 W / cm^ThreeSet to
Applied to the bias bar 428 to generate a glow discharge.
And open the shutter 427 to set the n / i buffer
The fabrication of the RFi-type layer on the layer 252 is started, and the layer thickness 110n
When the i-type layer of m was produced, the RF glow discharge was stopped,
Turning off the output of the RF power supply 424 to form the RFi-type layer 207
Finished. Close valves 464 and 454 to deposit i-type layer
Si into chamber 418_TwoH₆Stop the gas flow, 2
Minutes into the i-type layer deposition chamber 418_TwoContinue flowing gas
After that, the valves 453 and 450 are closed and the i-type layer deposition chamber is closed.
1 × 10 in chamber 418 and gas pipe^-FiveTor
e was evacuated to r.

Next, ap / i buffer layer 262 made of a-Sic was formed by RFPCVD. To form the p / i buffer layer 262, the substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 200 ° C., and when the substrate is sufficiently heated, the valves 464 and 45 are formed.
4, 450, 463, 453, 465, and 455 were gradually opened, and Si ₂ H ₆ gas, H ₂ gas, and CH ₄ gas were caused to flow into the i-type layer deposition chamber 418 through the gas introduction pipe 449. At this time, the flow rate of the Si ₂ H ₆ gas is 0.4 sccm,
H ₂ gas flow rate is 65 sccm, CH ₄ gas flow rate is 0.3 s
Each mass flow controller 4 so that it becomes ccm
Adjustment was made at 59, 458 and 460. The opening of the conductance valve (not shown) was adjusted so that the pressure in the i-type layer deposition chamber 418 became 1.1 Torr. Next, R
The F power source 424 was set to 0.06 W / cm ³ , applied to the bias bar 428 to generate a glow discharge, and opened the shutter 427 to start the production of the p / i buffer layer on the RFi-type layer. When a 15 nm thick p / i buffer layer was formed, the RF glow discharge was stopped and the RF power source 4 was turned off.
The output of 24 was turned off, and the production of the p / i buffer layer 262 was completed. Valves 464, 454, 465, 455 are closed and Si ₂ H ₆ gas into i-type layer deposition chamber 418,
After stopping the flow of the CH ₄ gas and continuing the flow of the H ₂ gas into the i-type layer deposition chamber 418 for 2 minutes, the valve 453,
450 was closed, and the inside of the i-type layer deposition chamber 418 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Next, a hydrogen plasma treatment containing trace amounts of Group III elements according to the present invention was performed under the conditions shown in Table 2 (2). In order to carry out the hydrogen plasma treatment containing a trace amount of a group III element according to the present invention, a BF ₃ / H ₂ (dilution ratio: 1%) gas as a group III element-containing gas
SiH ₄ gas and H ₂ gas are introduced as gas containing silicon atoms into the deposition chamber 418 through the gas introduction pipe 449, and the valves 463, 453, and 450 are opened so that the H ₂ gas flow becomes 1300 sccm, and the mass flow controller 458 adjusts. did. Group III element-containing gas BF ₃ /
H ₂ gas was adjusted by the mass flow controller 467 opens the valve 468,466 to be 0.3% with respect to the total H ₂ gas flow rate. The valves 461 and 451 are opened so that the silicon atom-containing gas and the SiH ₄ gas become 0.03% of the total H ₂ gas flow rate.
Adjusted at 56. The pressure in the deposition chamber 418 is set to 0.
It was adjusted with a conductance valve (not shown) so that the pressure became 7 Torr. The substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 200 ° C., and when the substrate temperature is stabilized, the power of the RF power supply 424 is reduced to 0.04 W / cm.
³ , and RF power was applied to the bias bar 428.
A glow discharge was generated in the deposition chamber 418, the shutter 427 was opened, and the hydrogen plasma treatment containing a trace amount of Group III element of the present invention was performed for 3 minutes. Thereafter, the RF power source is turned off, the glow discharge is stopped, and B
F ₃ / H ₂ gas, stopping the flow of SiH ₄ gas, 3 minutes, after which continued to flow H ₂ gas into the deposition chamber 418, H ₂
The flow of gas was also stopped, and the inside of the deposition chamber 418 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Next, an RFp type layer 208 made of a-SiC
In order to form the substrate, the gate valve 408 was opened and the substrate 490 was transferred into the transfer chamber 404 and the p-type layer deposition chamber 419 that were previously evacuated by a vacuum pump (not shown). The back surface of the substrate 490 was heated by being brought into close contact with a heater 412 for heating the substrate, and the inside of the p-type layer deposition chamber 419 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

The temperature of the substrate 490 is set to 170 ° C.
Set the substrate heating heater 412 to keep the substrate temperature stable.
By the way, H_TwoGas, SiH_Four/ H_TwoGas, B_TwoH₆/ H_Two
Gas, CH_FourThe gas is introduced into the deposition chamber 419 by the valve 4.
81, 471, 470, 482, 472, 483, 47
Operate 3, 484, 474 through gas introduction pipe 469
Introduced. At this time, H_TwoGas flow rate 70scm, Si
H_Four/ H_TwoGas flow rate 2sccm, B_TwoH₆/ H_TwoGas flow
Is 10 sccm, CH_FourGas flow becomes 0.3sccm
Like the mass flow controllers 476, 477, 47
8 and 479, the pressure in the deposition chamber 419 is
A conductance bar (not shown) is set to 1.7 Torr.
The lube opening was adjusted. The power of the RF power supply 423 is set to 0.0
7W / cm ^ThreeTo the plasma forming cup 421
RF power is introduced to generate glow discharge, and p / i battery
The formation of the RFp type layer on the fur layer 262 is started, and the layer thickness 1
When the 0 nm RFp type layer is formed, the RF power is turned off.
To stop the glow discharge and finish forming the RFp type layer 208.
Was. Valves 472, 482, 473, 483, 474,
484 is closed and the Si is introduced into the p-type layer deposition chamber 419.
H_Four/ H_TwoGas, B_TwoH₆/ H_TwoGas, CH_FourStop gas flow
For 2 minutes into the p-type layer deposition chamber 419_Twogas
And then close valves 471, 481, and 470
H_TwoOf p-type layer deposition chamber 419
And 1 × 10^-FiveEvacuate to Torr
Was.

Next, the gate valve 409 is opened into the unload chamber 405 evacuated by a vacuum pump (not shown), and the substrate 490 is transported. The leak valve (not shown) is opened to open the unload chamber 40.
5 leaked. Next, as the transparent conductive layer 212, ITO with a thickness of 70 nm was vacuum-deposited on the RFp-type layer 208 by a vacuum deposition method.

Next, a mask having a comb-shaped hole is placed on the transparent conductive layer 212 and Cr (40 nm) / Ag (1000 n
m) / Cr (40 nm) comb-shaped current collecting electrode 213
Was vacuum deposited by a vacuum deposition method. Thus, the production of the solar cell has been completed. We call this solar cell (SC Ex. 2)
Hydrogen plasma treatment conditions containing trace amounts of Group III elements of the present invention,
RF n-type layer, n / i buffer layer, MWi-type layer, p / i
The formation conditions of the buffer layer, RFi-type layer, and RFp-type layer are shown in Tables 2 (1) to 2 (3).

<Comparative Example 2> A solar cell (SC ratio 2) was manufactured under the same conditions as in Example 2 except that the hydrogen plasma treatment containing trace amounts of Group III elements of the present invention was not performed. Nine solar cells (SC actual 2) and (SC ratio 2) were manufactured, each having nine photoelectric conversion efficiencies (photovoltaic power / incident optical power), vibration deterioration, light deterioration, and high temperature and high humidity when bias voltage was applied. Vibration degradation and light degradation in the environment were measured.

The initial photoelectric conversion efficiency can be obtained by placing the manufactured solar cell under AM1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristics. As a result of the measurement, the fill factor (FF) of the initial photoelectric conversion efficiency of (SC actual 2) and the series resistance (R
s) and characteristic unevenness were as follows. Fill factor Series resistance Characteristic unevenness (SC Ex. 2) 1.15 times 0.90 times 0.82 times For the measurement of vibration deterioration, a solar cell whose initial photoelectric conversion efficiency was measured in advance was a humidity of 54% and a temperature of 26 ° C. In a dark place with a vibration frequency of 60 Hz and an amplitude of 0.1 mm
AM1.5 (100 mW / cm ² ) after adding for 0 hours
The measurement was performed based on the rate of decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after vibration degradation test / initial photoelectric conversion efficiency).

For the measurement of photodegradation, a solar cell whose initial photoelectric conversion efficiency was measured in advance was placed in an environment of a humidity of 54% and a temperature of 26 ° C., and was irradiated with AM1.5 (100 mW / cm ² ) light for 550 hours. After irradiation, AM1.5 (100 mW / c
m ² ) The rate of decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after light degradation test / initial photoelectric conversion efficiency). As a result of the measurement, the rate of decrease in photoelectric conversion efficiency after photodegradation (SC ratio 2) and the rate of decrease in photoelectric conversion efficiency after vibration degradation with respect to (SC actual 2) were as follows.

[0129] Vibration degradation and light degradation in a high temperature and high humidity environment at the time of bias application were measured. Two solar cells whose initial photoelectric conversion efficiencies were measured in advance were placed in a dark place at a humidity of 90% and a temperature of 81 ° C., and 0.71 V was applied as a forward bias voltage. The above-mentioned vibration was applied to one of the solar cells to measure the vibration degradation, and the other solar cell was subjected to AM1.
The sample was irradiated with the light of No. 5 to measure photodegradation. As a result of the measurement, the reduction rate of the photoelectric conversion efficiency after the vibration deterioration of (SC ratio 2) and the reduction rate of the photoelectric conversion efficiency after the light deterioration of (SC ratio 2) are as follows with respect to (SC actual 2).

[0130] The state of delamination was observed using an optical microscope. In (SC Ex. 2), no delamination was observed, but in (SC ratio 2), delamination was slightly observed. As described above, the solar cell (SC Ex. 2) of the present invention has a better fill factor, series resistance, characteristic unevenness, light degradation characteristic, adhesion, and so on than the conventional solar cell (SC ratio 2) in the photoelectric conversion efficiency of the solar cell. It was found that it had more excellent properties in durability.

Example 3 Using the deposition apparatus shown in FIG. 4, the triple solar cell shown in FIG. 3 was manufactured. Reflection layer 301 and reflection enhancement layer 30 prepared by the same method as in Example 1.
2 is formed in the load chamber 40.
The load chamber 401 was evacuated by a vacuum evacuation pump (not shown) until the pressure reached about 1 × 10 ⁻⁵ Torr.

Next, the gate valve 406 was opened and transported into the transport chamber 402 and the deposition chamber 417, which were previously evacuated by a vacuum pump (not shown). The back surface of the substrate 490 was heated by being brought into close contact with a heater 410 for heating the substrate, and the inside of the deposition chamber 417 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

After the preparation for the film formation is completed as described above, Rc of μc-Si is formed in the same manner as in the second embodiment.
An Fn type layer 303 was formed. Next, the gate valve 40 is put into the transfer chamber 403 and the deposition chamber 418 that have been evacuated by a vacuum pump (not shown) in advance.
7 was opened and transported. The back surface of the substrate 490 is brought into close contact with the substrate heating heater 411 and heated, and the deposition chamber 418 is heated.
The pressure is about 1 × 10 ^-5 by a vacuum pump (not shown).
The system was evacuated to Torr.

Next, aS is performed in the same manner as in the second embodiment.
The n / i buffer layer 351 made of i, the MWi type layer 304 made of a-SiGe, and the p / i buffer layer 361 made of a-Si are formed by RFPCVD, MWPCVD, R
The layers were sequentially formed by the FPCVD method. Next, the trace amount of the present invention
The group III element-containing hydrogen plasma treatment was performed under the conditions shown in Table 3 (1). In order to carry out the hydrogen plasma treatment containing trace amounts of Group III elements according to the present invention, B ₂ H ₆ / H ₂
(Dilution: 10%) gas, SiCl ₂ H ₂ / He (dilution: 1000 ppm) gas as a silicon atom-containing gas,
H ₂ gas is introduced into the deposition chamber 418 by a gas introduction pipe 449.
The valves 463, 453, and 450 were opened so that the flow rate of H ₂ gas became 1500 sccm, and the mass flow controller 458 adjusted. Group III element-containing gas B ₂ H ₆ / H ₂ gas is 2.0% of the total H ₂ gas flow rate
Were adjusted by the mass flow controller 467 by opening the valves 468 and 466. The silicon atom-containing gas, SiCl ₂ H ₂ / He (dilution: 1000 ppm), has a ratio of SiCl ₂ H ₂ gas of 0.1 to the total H ₂ gas flow rate.
The valve (not shown) was opened so that the concentration became 03%, and adjustment was performed using a mass flow controller (not shown). Deposition chamber 41
8 was adjusted by a conductance valve (not shown) so that the pressure in the chamber 8 became 0.008 Torr. The substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 330 ° C., and when the substrate temperature is stabilized, the power of the MW power supply (not shown) is set to 0.15 W / cm ³ , and the waveguide 426 and the MW power is introduced into the i-type layer deposition chamber 418 through the microwave introduction window 425 to generate glow discharge,
By opening the shutter 427, the hydrogen plasma treatment containing trace amounts of Group III elements of the present invention was performed for 4 minutes. Then M
Turn off the power and stop the glow discharge.
B ₂ H ₆ / H ₂ (10% dilution) gas, SiC
l ₂ H ₂ / He (dilution: 1000 ppm) to stop the flow of gas, 4 minutes, after continued to flow H ₂ gas into the deposition chamber 418, stopping the inflow of H ₂ gas, the deposition chamber 418 and the gas pipe The inside was evacuated to 1 × 10 ⁻⁵ Torr.

Next, aS was obtained in the same manner as in Example 2.
RFp type layer 305 made of iC, R made of μc-Si
Fn type layer 306, n / i buffer layer 352 made of a-Si, MWi type layer 307 made of a-SiGe, a-
RF / PCVD of p / i buffer layer 362 made of Si
And the MWPCVD method. Next, the hydrogen plasma treatment containing trace amounts of Group III elements according to the present invention is shown in Table 3 (2).
Was performed under the following conditions.

In order to carry out the hydrogen plasma treatment containing a trace amount of group III element according to the present invention, B ₂ H
₆ / H ₂ (dilution: 10%) gas and SiH ₄ gas and H ₂ gas as silicon atom-containing gas are deposited in a deposition chamber 418.
Introduced through the gas inlet pipe 449 within the valve as H ₂ gas flow rate was 1200 sccm 463,453,
450 was opened and adjusted by the mass flow controller 458. Group III element-containing gas B ₂ H ₆ / H ₂ (dilution 10
%) The valves 468 and 466 were opened and the mass flow controller 467 adjusted the gas so that the gas became 1.0% of the total H ₂ gas flow rate. Silicon atom containing gas, SiH ₄
The valves 461 and 451 were opened and the mass flow controller 456 adjusted the gas so that the gas became 0.03% of the total H ₂ gas flow rate. The conductance valve (not shown) was adjusted so that the pressure in the deposition chamber 418 became 0.7 Torr. The substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 280 ° C., and when the substrate temperature is stabilized, the power of the RF power supply 424 is reduced to 0.04 W /
cm ³ , and RF power is applied to the bias bar 428 to generate a glow discharge in
Was opened, and a hydrogen plasma treatment containing trace amounts of Group III elements of the present invention was performed for 3 minutes. Thereafter, the RF power is turned off to stop the glow discharge, and B ₂ H ₆ / H into the deposition chamber 418.
₂ (Dilution: 10%) Stop the flow of gas and SiH ₄ gas,
After continuously flowing the H ₂ gas into the deposition chamber 418 for 3 minutes, the flow of the H ₂ gas is stopped, and the deposition chamber 418 is stopped.
The inside and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Next, aS was obtained in the same manner as in Example 2.
RFp type layer 308 made of iC, R made of μc-Si
Fn type layer 309, n / i buffer layer 353 made of a-SiC, RFi type layer 310 made of a-Si, a-S
RF / PCVD of p / i buffer layer 363 made of iC
It was sequentially formed by the method. Next, hydrogen plasma treatment containing trace amounts of Group III elements according to the present invention was performed under the conditions shown in Table 3 (3). In order to carry out the hydrogen plasma treatment containing trace amounts of group III elements according to the present invention, a B ₂ H ₆ / H ₂ (dilution: 10%) gas as a group III element-containing gas and a Si atom-containing gas as a silicon atom-containing gas are used.
H ₄ gas and H ₂ gas are introduced into the deposition chamber 418 through the gas introduction pipe 449, and the H ₂ gas flow rate is 1400 sc.
cm, the valves 463, 453, and 450 were opened and adjusted by the mass flow controller 458. II
The valves 468 and 466 were opened and the mass flow controller 467 was adjusted so that the group I element-containing gas B ₂ H ₆ / H ₂ gas became 0.5% of the total H ₂ gas flow rate. The valves 461 and 451 were opened and the mass flow controller 456 adjusted the silicon atom-containing gas so that the ratio of the SiH ₄ gas to the total H ₂ gas flow was 0.03%. The pressure in the deposition chamber-418 was adjusted with a conductance valve (not shown) so as to be 0.8 Torr. Substrate 49
Substrate heating heater 4 so that the temperature of
11 was set, and when the substrate temperature was stabilized, the power of the RF power supply 424 was set to 0.04 W / cm ³ , RF power was applied to the bias rod 428, a glow discharge was generated in 418, and the shutter 427 was opened. The hydrogen plasma treatment containing trace amounts of Group III elements according to the present invention was performed for 3 minutes. Then R
Turn off the F power, stop the glow discharge, and set the deposition chamber 4
B ₂ H ₆ / H ₂ (dilution: 10%) gas, Si
Stop the flow of the H ₄ gas and stop the deposition chamber 418 for 3 minutes.
After continuing to flow H ₂ gas into the inside, the inflow of H ₂ gas was stopped,
1 × 10 ⁻⁵ in the deposition chamber 418 and the gas pipe
Evacuated to Torr.

Next, aS was obtained in the same manner as in Example 2.
An RFp type layer 311 made of iC was formed by an RFPCVD method. Next, as the transparent conductive layer 312, ITO having a thickness of 70 nm was vacuum-deposited on the RFp-type layer 311 by a vacuum deposition method. Next, a mask having a comb-shaped hole is placed on the transparent conductive layer 312, and Cr (40 nm) / Ag (1000 n
m) / Cr (40 nm) comb-shaped current collecting electrode 313
Was vacuum deposited by a vacuum deposition method.

Thus, the production of the solar cell has been completed. This solar cell is referred to as (SC Ex. 3), and is referred to as a trace II of the present invention.
Group I element-containing hydrogen plasma treatment conditions, RF n-type layer, n /
i buffer layer, MWi type layer, p / i buffer layer, R
Tables 3 (1) and 3 show the conditions for forming the Fi-type layer and the RFp-type layer.
(2), 3 (3), and 3 (4) are shown. <Comparative Example 3> A solar cell (SC ratio 3) was manufactured under the same conditions as in Example 3 except that the hydrogen plasma treatment containing trace amounts of Group III elements of the present invention was not performed.

Six solar cells (SC Ex. 3) and (SC ratio 3) were manufactured, each having six initial photoelectric conversion efficiencies (photovoltaic power / incident optical power), vibration deterioration, light deterioration, and high temperature when bias voltage was applied. Vibration degradation, light degradation, and reverse bias voltage application characteristics in a high humidity environment were measured. The initial photoelectric conversion efficiency was measured using an AM1.5 (100 m
(W / cm ² ) It is obtained by measuring under the irradiation of light and measuring VI characteristics. As a result of the measurement, the fill factor (F) of the initial photoelectric conversion efficiency of (SC actual 3) with respect to (SC ratio 3)
F), series resistance (Rs) and characteristic unevenness were as follows.

Curve factor Series resistance Characteristic unevenness (SC ratio 3) 1.14 times 0.89 times 0.83 times The vibration deterioration was measured by measuring the initial photoelectric conversion efficiency of a solar cell in advance at a humidity of 55%. It was installed in a dark place at a temperature of 26 ° C.
AM1.5 (100 mW / cm ² ) after adding for 0 hours
The measurement was performed based on the rate of decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after vibration degradation test / initial photoelectric conversion efficiency).

The photodegradation was measured by placing a solar cell, whose initial photoelectric conversion efficiency was measured in advance, in an environment of a humidity of 55% and a temperature of 26 ° C., and applying AM1.5 (100 mW / cm ² ) light for 550 hours. After irradiation, AM1.5 (100 mW / c
m ² ) The rate of decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after light degradation test / initial photoelectric conversion efficiency). As a result of the measurement, the rate of decrease in photoelectric conversion efficiency after light deterioration (SC ratio 3) and the rate of decrease in photoelectric conversion efficiency after vibration deterioration with respect to (SC actual 3) were as follows.

[0143] Vibration degradation and light degradation in a high temperature and high humidity environment at the time of bias application were measured. Two solar cells whose initial photoelectric conversion efficiencies were measured in advance were placed in a dark place with a humidity of 93% and a temperature of 82 ° C., and 0.71 V was applied as a forward bias voltage. The above-mentioned vibration was applied to one of the solar cells, and the deterioration of the vibration was measured.
Was irradiated to measure the photodegradation.

As a result of the measurement, (S
The reduction rate of the photoelectric conversion efficiency after the vibration deterioration of C ratio 3) and the reduction rate of the photoelectric conversion efficiency after the light deterioration were as follows. The measurement of the reverse bias voltage application characteristic is performed by measuring the initial photoelectric conversion efficiency of a solar cell at a humidity of 52% and a temperature of 8%.
It was installed in a dark place at 0 ° C., and the reverse bias voltage was 5.0 V,
After applying for 100 hours, AM1.5 (100 mW / cm
² ) The photoelectric conversion efficiency under irradiation was measured, and the reduction rate (photoelectric conversion efficiency after application of reverse bias voltage / initial photoelectric conversion efficiency) was used.

As a result of the measurement, (S
The reduction ratio of the C ratio 3) after application of the reverse bias voltage was as follows. (SC ratio 3) 0.86 times The state of delamination was observed using an optical microscope. In (SC Ex. 3), no delamination was observed, but in (SC ratio 3), delamination was slightly observed.

As described above, the solar cell (SC Ex. 3) of the present invention has a better fill factor, series resistance, characteristic unevenness, light degradation characteristic in the photoelectric conversion efficiency of the solar cell than the conventional solar cell (SC ratio 3). It was found that it had further excellent characteristics in adhesion, durability, and reverse bias voltage application characteristics. (Embodiment 4) As in Embodiment 3, using the deposition apparatus shown in FIG. 4, the hydrogen plasma treatment containing trace amounts of Group III elements of the present invention was performed three times under the conditions shown in Table 4 (1). Then, the triple solar cell of FIG. 3 was produced. Table 4 (1) shows the conditions for the treatment with the hydrogen plasma containing a trace amount of Group III element, and Table 4 (2) shows the manufacturing conditions for the triple solar cell.

In the same manner as in Example 3, the manufactured triple solar cell was evaluated. The results are shown in Table 4 (3).
The hydrogen flow rate of the trace plasma of the Group III element-containing hydrogen plasma treatment of the present invention is 1 to 3 in the fill factor of the photoelectric conversion efficiency of the solar cell, the characteristic unevenness, the light deterioration characteristic, the series resistance characteristic, the durability, and the reverse bias voltage application characteristic. 2000sccm
Was found to be a suitable flow rate.

(Example 5) In the same manner as in Example 3, the deposition apparatus shown in FIG. 4 was used to carry out the hydrogen plasma treatment containing trace amounts of Group III elements three times under the conditions shown in Table 5 (1). 3, the triple solar cell of FIG. Table 5 (1) shows the hydrogen plasma treatment conditions containing trace amounts of Group III elements.
Table 5 (2) shows the manufacturing conditions of the triple solar cell.

[0149] In the same manner as in Example 3, the produced triple type solar cell was evaluated. The results are shown in Table 5 (3).
Even if the input power for the hydrogen plasma treatment containing trace amounts of Group III elements of the present invention is changed from the RF power supply of the fourth embodiment to the VHF power supply,
Fill factor, characteristic unevenness in photoelectric conversion efficiency of solar cell,
The hydrogen flow rate is 1 to 2000 sc in the light deterioration characteristics, series resistance characteristics, durability, and reverse bias voltage application characteristics.
cm was found to be a suitable flow rate.

(Example 6) In the same manner as in Example 3, the deposition apparatus shown in FIG. 4 was used to carry out the hydrogen plasma treatment containing trace amounts of Group III elements three times under the conditions shown in Table 6 (1). 3, the triple solar cell of FIG. Table 6 (1) shows the hydrogen plasma treatment conditions containing trace amounts of Group III elements.
Table 6 (2) shows the manufacturing conditions of the triple solar cell.

In the same manner as in Example 3, the manufactured triple solar cell was evaluated. The results are shown in Table 6 (3).
The amount of the Group III element-containing gas added to the hydrogen gas in the trace Group III element-containing hydrogen plasma treatment of the present invention is as follows:
Fill factor, characteristic unevenness in photoelectric conversion efficiency of solar cell,
In light deterioration characteristics, series resistance characteristics, durability, and reverse bias voltage application characteristics, 0.05% to 3% were found to be preferable ranges.

Example 7 In the same manner as in Example 3, the deposition apparatus shown in FIG. 4 was used to carry out the hydrogen plasma treatment containing trace amounts of Group III elements three times under the conditions shown in Table 7 (1). 3, the triple solar cell of FIG. Table 7 (1) shows the hydrogen plasma treatment conditions containing the collected Group III element.
Table 7 (2) shows the conditions for manufacturing the triple type solar cell.

As in Example 3, the fabricated triple solar cell was evaluated. The results are shown in Table 7 (3).
The addition amount of the Group III element-containing gas to be added to the hydrogen gas in the trace Group III element-containing hydrogen plasma treatment of the present invention can be changed even if the input power is changed from the RF power supply of Embodiment 6 to the VHF power supply. It has been found that 0.05% to 3% are preferable ranges in terms of the fill factor in photoelectric conversion efficiency, characteristic unevenness, light deterioration characteristic, series low resistance characteristic, durability, and reverse bias voltage application characteristic.

(Embodiment 8) In the same manner as in Embodiment 3, using the deposition apparatus shown in FIG. 4, the hydrogen plasma treatment containing trace amounts of Group III elements of the present invention was performed three times under the conditions shown in Table 8 (1). 3, the triple solar cell of FIG. Table 8 (1) shows the hydrogen plasma treatment conditions containing trace amounts of Group III elements.
Table 8 (2) shows the conditions for manufacturing the triple solar cell.

In the same manner as in Example 3, the manufactured triple solar cell was evaluated. The results are shown in Table 8 (3).
The addition amount of the Group III element-containing gas added to the hydrogen gas in the trace Group III element-containing hydrogen plasma treatment of the present invention can be obtained by changing the input power from the RF power supply of the sixth embodiment to the MW power supply.
Fill factor, characteristic unevenness in photoelectric conversion efficiency of solar cell,
It has been found that 0.05% to 3% is a preferable range in the light deterioration characteristic, the series resistance characteristic, the durability, and the reverse bias voltage application characteristic.

(Example 9) In the same manner as in Example 3, the deposition apparatus shown in FIG. 4 was used to carry out the hydrogen plasma treatment containing trace amounts of Group III elements three times under the conditions shown in Table 9 (1). 3, the triple solar cell of FIG. Table 9 (1) shows the hydrogen plasma treatment conditions containing trace amounts of Group III elements.
Table 9 (2) shows the manufacturing conditions of the triple solar cell.

In the same manner as in Example 3, the manufactured triple solar cell was evaluated. The results are shown in Table 9 (3).
The amount of the silicon atom-containing gas added to the hydrogen gas in the trace Group III element-containing hydrogen plasma treatment of the present invention is:
Fill factor, characteristic unevenness in photoelectric conversion efficiency of solar cell,
It has been found that 0.001% to 0.1% is a preferable range in light deterioration characteristics, series resistance characteristics, durability, and reverse bias voltage application characteristics.

Example 10 In the same manner as in Example 3, the deposition apparatus shown in FIG. 4 was used to carry out the hydrogen plasma treatment containing a trace amount of Group III element three times under the conditions shown in Table 10 (1).
A triple solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing trace amounts of Group III elements.
Table 10 shows the manufacturing conditions of the triple solar cell at 0 (1).
This is shown in (2).

In the same manner as in Example 3, the fabricated triple type solar cell was evaluated. The results are shown in Table 10 (3). The addition amount of the silicon atom-containing gas to be added to the hydrogen gas in the hydrogen plasma treatment containing trace amounts of Group III elements according to the present invention can be changed even if the input power is changed from the RF power supply of Embodiment 9 to the VHF power supply. The fill factor in the efficiency, the characteristic unevenness, the optical deterioration characteristic, the series resistance characteristic, the durability, and the reverse bias voltage application characteristic are 0.001% to 0.1%.
1% was found to be a preferred range.

(Example 11) In the same manner as in Example 3, the deposition apparatus shown in FIG. 4 was used to perform the hydrogen plasma treatment containing a trace amount of Group III element three times under the conditions shown in Table 11 (1).
A triple solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing trace amounts of Group III elements.
Table 1 shows the manufacturing conditions for the triple type solar cell.
This is shown in (2).

In the same manner as in Example 3, the manufactured triple solar cell was evaluated. The results are shown in Table 11 (3). The addition amount of the silicon atom-containing gas to be added to the hydrogen gas in the hydrogen plasma treatment of the trace Group III element-containing hydrogen gas of the present invention can be changed even if the input power is changed from the RF power supply of the ninth embodiment to the MW power supply. 0.001% to 0.1 in curve factor in efficiency, characteristic unevenness, light degradation characteristic, series resistance characteristic, durability, and reverse bias voltage application characteristic
% Was found to be a preferred range.

(Example 12) In the same manner as in Example 3, the deposition apparatus shown in FIG. 4 was used to carry out the hydrogen plasma treatment containing trace amounts of Group III elements three times under the conditions shown in Table 12 (1).
A triple solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing trace amounts of Group III elements.
Table 12 shows the production conditions for the triple solar cell in Table 2 (1).
This is shown in (2).

In the same manner as in Example 3, the manufactured triple solar cell was evaluated. The results are shown in Table 12 (3). The pressure of the hydrogen plasma treatment containing a trace amount of Group III element of the present invention, when an RF power supply is used as the input power, a fill factor in the photoelectric conversion efficiency of the solar cell, characteristic unevenness, light deterioration characteristic, series resistance characteristic, durability, It has been found that 0.05 Torr to 10 Torr is a preferable range in the reverse bias voltage application characteristics.

Example 13 In the same manner as in Example 3, the deposition apparatus shown in FIG. 4 was used to carry out the hydrogen plasma treatment containing trace amounts of Group III elements three times under the conditions shown in Table 13 (1).
A triple solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing trace amounts of Group III elements.
Table 13 shows the manufacturing conditions of the triple solar cell in 3 (1).
This is shown in (2).

As in Example 3, the fabricated triple solar cell was evaluated. The results are shown in Table 13 (3). When a VHF power supply is used as the input power, the pressure of the trace Group III element-containing hydrogen plasma treatment of the present invention is a fill factor in the photoelectric conversion efficiency of the solar cell, characteristic unevenness, light deterioration characteristic, series resistance characteristic, durability, Reverse bias voltage application characteristics from 0.0001 Torr to 1 Torr
Was found to be a preferable range.

Example 14 In the same manner as in Example 3, the deposition apparatus shown in FIG. 4 was used to carry out the hydrogen plasma treatment containing trace amounts of Group III elements three times under the conditions shown in Table 14 (1).
A triple solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing trace amounts of Group III elements.
Table 14 shows the conditions for manufacturing the triple type solar cell.
This is shown in (2).

In the same manner as in Example 3, the manufactured triple solar cell was evaluated. The results are shown in Table 14 (3). The pressure of the hydrogen plasma treatment containing a trace amount of group III element of the present invention, when using a MW power supply as the input power, the fill factor in the photoelectric conversion efficiency of the solar cell, characteristic unevenness, light degradation characteristics, series resistance characteristics, durability, Reverse bias voltage application characteristics from 0.0001 Torr to 0.01 To
rr was found to be in the preferred range.

(Example 15) In the same manner as in Example 3, the deposition apparatus shown in FIG. 4 was used to carry out the hydrogen plasma treatment containing a trace amount of Group III element three times under the conditions shown in Table 15 (1).
A triple solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing trace amounts of Group III elements.
Table 15 shows the manufacturing conditions of the triple solar cell in Table 15 (1).
This is shown in (2).

In the same manner as in Example 3, the manufactured triple solar cell was evaluated. The results are shown in Table 15 (3). The input power density (electric energy) of the hydrogen plasma treatment containing trace amounts of Group III elements according to the present invention is as follows: when an RF power source is used as the input power, the fill factor, the unevenness of the characteristics, the light degradation characteristics, 0.01 W / in resistance characteristics, durability, and reverse bias voltage application characteristics
cm ³ to 1.0 W / cm ³ was found to be a preferred range.

Example 16 In the same manner as in Example 3, the deposition apparatus shown in FIG. 4 was used to carry out the hydrogen plasma treatment containing a trace amount of Group III element three times under the conditions shown in Table 16 (1).
A triple solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing trace amounts of Group III elements.
Table 16 shows the manufacturing conditions of the triple solar cell in Table 6 (1).
This is shown in (2).

In the same manner as in Example 3, the manufactured triple solar cell was evaluated. The results are shown in Table 16 (3). When a VHF power supply is used as the input power, the input power density (electric energy) of the hydrogen plasma treatment containing trace amounts of Group III elements according to the present invention is as follows: the fill factor in the photoelectric conversion efficiency of the solar cell; 0.01 W / in resistance characteristics, durability, and reverse bias voltage application characteristics
cm ³ to 1.0 W / cm ³ was found to be a preferred range.

(Example 17) In the same manner as in Example 3, the deposition apparatus shown in FIG. 4 was used to carry out the hydrogen plasma treatment containing a trace amount of Group III element three times under the conditions shown in Table 17 (1).
A triple solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing trace amounts of Group III elements.
Table 17 shows the manufacturing conditions of the triple solar cell in Table 7 (1).
This is shown in (2).

In the same manner as in Example 3, the manufactured triple solar cell was evaluated. The results are shown in Table 17 (3). The input power density (power amount) of the hydrogen plasma treatment containing a trace amount of group III element according to the present invention is as follows: when an MW power source is used as the input power, the fill factor in the photoelectric conversion efficiency of the solar cell, the characteristic unevenness, the light degradation characteristic, and the series resistance characteristics were found to be 10 W / cm ³ from 0.1 W / cm ³ in the durability and the preferred range.

Example 18 In the same manner as in Example 3, the deposition apparatus shown in FIG. 4 was used to carry out the hydrogen plasma treatment containing a trace amount of Group III element three times under the conditions shown in Table 18 (1).
A triple solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing trace amounts of Group III elements.
8 (1) shows the manufacturing conditions of the triple solar cell in Table 18
This is shown in (2).

In the same manner as in Example 3, the manufactured triple solar cell was evaluated. The results are shown in Table 18 (3). The substrate temperature of the hydrogen plasma treatment containing trace amounts of Group III elements according to the present invention is determined by using an RF power supply as the input power, the fill factor in the photoelectric conversion efficiency of the solar cell, the characteristic unevenness, the light deterioration characteristic, the series resistance characteristic, and the durability. In the reverse bias voltage application characteristics, it was found that 100 ° C. to 400 ° C. was a preferable range.

Example 19 In the same manner as in Example 3, the deposition apparatus shown in FIG. 4 was used to carry out the hydrogen plasma treatment containing a trace amount of Group III element three times under the conditions shown in Table 19 (1).
A triple solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing trace amounts of Group III elements.
Table 19 shows the manufacturing conditions of the triple solar cell in Table 9 (1).
This is shown in (2).

In the same manner as in Example 3, the manufactured triple solar cell was evaluated. The results are shown in Table 19 (3). The substrate temperature of the hydrogen plasma treatment containing a trace amount of group III element according to the present invention is as follows: when a VHF power supply is used as the input power, the fill factor in the photoelectric conversion efficiency of the solar cell, uneven characteristics, light deterioration characteristics, series resistance characteristics, and durability It was found that the preferable range was 50 ° C. to 300 ° C. in the reverse bias voltage application characteristics.

(Example 20) In the same manner as in Example 3, the deposition apparatus shown in FIG. 4 was used to carry out the hydrogen plasma treatment containing trace amounts of Group III elements three times under the conditions shown in Table 20 (1).
A triple solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 2 shows the hydrogen plasma treatment conditions containing trace amounts of Group III elements.
Table 20 shows the manufacturing conditions of the triple solar cell at 0 (1).
This is shown in (2).

In the same manner as in Example 3, the manufactured triple solar cell was evaluated. The results are shown in Table 20 (3). The substrate temperature of the hydrogen plasma treatment containing trace amounts of Group III elements according to the present invention is as follows: when an MW power source is used as input power, a fill factor in photoelectric conversion efficiency of a solar cell, uneven characteristics, light degradation characteristics, series resistance characteristics, It turned out that 50 to 300 degreeC is a preferable range in durability.

Example 21 Using the deposition apparatus shown in FIG. 4, the triple solar cell shown in FIG. 3 was manufactured. Reflection layer 301 and reflection enhancement layer 3 prepared by the same method as in Example 1.
02 is formed on the load chamber 4
The load chamber 401 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

Next, the gate valve 406 was opened and transferred into the transfer chamber 402 and the deposition chamber 417, which were previously evacuated by a vacuum pump (not shown). The back surface of the substrate 490 was heated by being brought into close contact with a heater 410 for heating the substrate, and the inside of the deposition chamber 417 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

Next, hydrogen plasma treatment containing a trace amount of silane-based gas was performed under the conditions shown in Table 21 (1). To perform a hydrogen plasma treatment containing a trace amount of silane-based gas, a SiH ₄ / H ₂ (diluted degree: 1000 ppm) gas is used as a silicon atom-containing gas.
H ₂ gas is introduced into the deposition chamber 417 by a gas introduction pipe 429.
The valves 441, 431, and 430 were opened so that the H ₂ gas flow rate became 1200 sccm, and the mass flow controller 436 adjusted the flow rate. The gas containing silicon atoms was adjusted by the mass flow controller 437 by opening the valves 442 and 432 so that the ratio of the SiH ₄ gas to the total H ₂ gas flow was 0.03%. The pressure inside the deposition chamber 417 was adjusted with a conductance valve (not shown) so as to be 0.9 Torr. The substrate heating heater 410 is set so that the temperature of the substrate 490 becomes 360 ° C., and when the substrate temperature is stabilized, the RF power source 422 is set.
Was set to 0.03 W / cm ³ , RF power was introduced, glow discharge was generated in the plasma forming cup 420, and hydrogen plasma treatment containing a trace amount of silane-based gas was performed for 3 minutes. After that, turn off the RF power, stop the glow discharge,
SiH ₄ / H ₂ into the deposition chamber 417 (dilution: 1)
000 ppm) to stop the flow of gas, 5 minutes, vacuum After continued to flow H ₂ gas into the deposition chamber 417, stopping the inflow of the H ₂ gas, the inside and the gas in the pipe the deposition chamber 417 to 1 × 10 ^-5 Torr Exhausted.

After the preparation for film formation is completed as described above, Rc of μc-Si is formed in the same manner as in Example 2.
An Fn type layer 303 was formed. Next, hydrogen plasma treatment containing a trace amount of silane-based gas was performed under the conditions shown in Table 21 (2). In order to perform hydrogen plasma treatment containing a trace amount of silane-based gas, SiH ₄ / H ₂ (dilution degree: 1000
ppm) gas and H ₂ gas are introduced into the deposition chamber 417 through the gas introduction pipe 429, and the H ₂ gas flow rate is 950.
The valves 441, 431, and 430 were opened so that the flow rate became sccm, and adjustment was performed by the mass flow controller 436. The gas containing silicon atoms is SiH _{4 with} respect to the total H ₂ gas flow rate.
Valves 442, 4 so that the gas ratio is 0.02%
32 was opened and adjusted by the mass flow controller 437. The pressure inside the deposition chamber 417 was adjusted with a conductance valve (not shown) so as to be 0.9 Torr.
The substrate heating heater 410 is set so that the temperature of the substrate 490 becomes 350 ° C., and when the substrate temperature is stabilized,
The power of the RF power supply 422 is set to 0.03 W / cm ³ ,
RF power was introduced, glow discharge was generated in the plasma forming cup 420, and hydrogen plasma treatment containing a small amount of silane-based gas was performed for 3 minutes. Thereafter, the RF power supply is turned off, the glow discharge is stopped, and SiH ₄ /
Stop the flow of H ₂ (dilution: 1000 ppm) gas
After continuously flowing the H ₂ gas into the deposition chamber 417 for a minute, the flow of the H ₂ gas was stopped, and the inside of the deposition chamber 417 and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Next, the gate valve 407 was opened and transported into the transport chamber 403 and the deposition chamber 418, which were previously evacuated by a vacuum pump (not shown). The back surface of the substrate 490 was heated by being brought into close contact with a substrate heating heater 411, and the inside of the deposition chamber 418 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

Next, a-Si was formed in the same manner as in Example 2.
An n / i buffer layer 351 made of C was formed by RFPCVD. Next, a hydrogen plasma treatment containing a trace amount of silane-based gas was performed under the conditions shown in Table 21 (3). In order to perform the hydrogen plasma treatment containing a trace amount of silane-based gas, SiH ₄ gas and H ₂ gas are used as the silicon atom-containing gas in the deposition chamber 4.
18 through a gas introduction pipe 449, and the valves 463 and 45 are set so that the H ₂ gas flow rate becomes 700 sccm.
3, 450 was opened and adjusted by the mass flow controller 458. The valves 461 and 451 were opened and the mass flow controller 456 adjusted the gas containing silicon atoms to 0.04% of the flow rate of the H ₂ gas. The conductance valve (not shown) was adjusted so that the pressure in the deposition chamber 418 became 0.7 Torr. The substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 350 ° C.
Is set, and when the substrate temperature is stabilized, the RF power supply 42
4 was set to 0.03 W / cm ³ and the bias rod 4
RF power was applied to 28. Glow discharge was generated in the deposition chamber 418, the shutter 427 was opened, and hydrogen plasma treatment containing a trace amount of silane-based gas was performed for 3 minutes. Then turn off the RF power to stop the glow discharge, to stop the flow of SiH ₄ gas into the deposition chamber 418, after continued to flow for 3 minutes, H ₂ gas into the deposition chamber 418, H ₂
The flow of gas was also stopped, and the inside of the deposition chamber 418 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Next, a-Si was produced in the same manner as in Example 2.
The MWi type layer 304 made of Ge was formed by the MWPCVD method. Next, hydrogen plasma treatment containing a trace amount of silane-based gas was performed under the conditions shown in Table 21 (4). To do trace silane-based gas containing hydrogen plasma treatment, as the silicon atom-containing gas, SiH ₄ gas, introduced through the gas inlet pipe 449 and H ₂ gas into the deposition chamber 418, the H ₂ gas flow rate 9
The valves 463, 453, and 45 are set to be 00 sccm.
0 was opened and adjusted by the mass flow controller 458. The valves 461 and 451 were opened and the mass flow controller 456 adjusted the gas containing silicon atoms to 0.04% of the H ₂ gas flow rate. The conductance valve (not shown) was adjusted so that the pressure in the deposition chamber 418 became 0.6 Torr. The substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 330 ° C., and when the substrate temperature is stabilized, the RF power source 424 is set.
Is set to 0.03 W / cm ³ and the bias rod 42
8, RF power was applied. Glow discharge was generated in the deposition chamber 418, the shutter 427 was opened, and hydrogen plasma treatment containing a trace amount of silane-based gas was performed for 3 minutes. Thereafter, the RF power source is turned off, the glow discharge is stopped, the flow of SiH ₄ gas into the deposition chamber 418 is stopped, and the flow of H ₂ gas into the deposition chamber 418 is continued for 3 minutes, and then the flow of H ₂ gas is also stopped. The inside of the deposition chamber 418 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Next, a-Si was formed in the same manner as in Example 2.
A p / i buffer layer 361 made of C was formed by RFPCVD. Next, hydrogen plasma treatment containing trace amounts of Group III elements according to the present invention was performed under the conditions shown in Table 21 (5). In order to carry out the hydrogen plasma treatment containing trace amounts of group III elements according to the present invention, a B ₂ H ₆ / H ₂ (dilution: 10%) gas as a group III element-containing gas and a Si atom-containing gas as a silicon atom-containing gas are used.
H ₄ gas and H ₂ gas are introduced into the deposition chamber 418 through the gas introduction pipe 449, and the H ₂ gas flow rate is 1000 sc.
cm, the valves 463, 453, and 450 were opened and adjusted by the mass flow controller 458. II
The valves 468 and 466 were opened and the mass flow controller 467 adjusted so that the group I element-containing gas B ₂ H ₆ / H ₂ gas became 0.6% of the total H ₂ gas flow rate. The valves 461 and 451 were opened and the mass flow controller 456 adjusted the gas containing silicon atoms to 0.03% of the total H ₂ gas flow rate.

When the pressure in the deposition chamber 418 is 0.6 T
orr was adjusted by a conductance valve (not shown). The substrate heating heater 411 is set so that the temperature of the base slope 490 becomes 300 ° C. When the substrate temperature is stabilized, the power of the RF power supply 424 is set to 0.03 W / cm ³ , and the RF power is supplied to the bias rod 428. Was applied. Glow discharge was generated in the deposition chamber 418, the shutter 427 was opened, and the hydrogen plasma treatment containing trace amounts of Group III elements of the present invention was performed for 3 minutes. Thereafter, the RF power is turned off to stop glow discharge, and B ₂ H ₆ /
After stopping the flow of the H ₂ (dilution: 10%) gas and the SiH ₄ gas, the flow of the H ₂ gas into the deposition chamber 418 is continued for 3 minutes, and then the flow of the H ₂ gas is also stopped.
The inside of 18 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Next, a-Si was formed in the same manner as in Example 2.
RF p-type layer 305 made of C, RF made of μc-Si
The n-type layers 306 were sequentially formed by the RFPCVD method.
Next, a hydrogen plasma treatment containing a trace amount of silane-based gas is shown in Table 21.
The test was performed under the condition (6). To perform a hydrogen plasma treatment containing a trace amount of silane-based gas, a silicon atom-containing gas is
iH ₄ / H ₂ (dilution: 1000 ppm) gas and H ₂ gas are introduced into the deposition chamber 417 through the gas introduction pipe 429, and the valves 441, 431, and 430 are opened so that the H ₂ gas flow rate becomes 1200 sccm. It was adjusted by the controller 436. The ratio of the SiH ₄ gas to the total H ₂ gas flow rate is 0.0%.
The valves 442 and 432 were opened so as to be 4%, and adjustment was performed by the mass flow controller 437. Deposition chamber 4
17 was adjusted by a conductance valve (not shown) so that the pressure in the chamber 17 became 0.8 Torr. When the temperature of the substrate 490 is 3
The substrate heating heater 410 was set to be 00 ° C., and when the substrate temperature was stabilized, the power of the RF power supply 422 was set to 0.03 W / cm ³ , and RF power was introduced.
Glow discharge was generated in the plasma forming cup 420, and hydrogen plasma treatment containing a trace amount of silane-based gas was performed for 3 minutes. Thereafter, the RF power supply was turned off to stop glow discharge, and SiH ₄ / H ₂ (dilution: 10) was introduced into the deposition chamber 417.
(00 ppm) The flow of gas was stopped, and the H ₂ gas was kept flowing into the deposition chamber 417 for 3 minutes. Then, the flow of H ₂ gas was stopped, and the flow of H ₂ gas was stopped in the deposition chamber 417 and the gas pipe.
× 10 ^- were evacuated to ⁵ Torr.

Next, a-Si was produced in the same manner as in Example 2.
An n / i buffer layer 352 made of C was formed by RFPCVD. Next, hydrogen plasma treatment containing a trace amount of silane-based gas was performed under the conditions shown in Table 21 (7). To perform a hydrogen plasma treatment containing a trace amount of silane-based gas, SiH ₄ gas and H ₂ gas as silicon atom-containing gas are introduced into the deposition chamber 418 through the gas introduction pipe 449 so that the H ₂ gas flow rate becomes 1100 sccm. Valves 463, 4
Open 53, 450 and open the mass flow controller 458
Was adjusted. The valves 461 and 451 were opened and the mass flow controller 456 adjusted the gas containing silicon atoms to 0.03% of the flow rate of the H ₂ gas. The conductance valve (not shown) was adjusted so that the pressure in the deposition chamber 418 became 0.7 Torr. Substrate 490
Substrate heating heater 41 so that the temperature of
1 is set, and when the substrate temperature is stabilized, the RF power supply 4
24 was set to 0.03 W / cm ³ , and RF power was applied to the bias bar 428. Glow discharge was generated in the deposition chamber 418, the shutter 427 was opened, and hydrogen plasma treatment containing a trace amount of silane-based gas was performed for 3 minutes. Thereafter, the RF power supply is turned off, the glow discharge is stopped, the flow of SiH ₄ gas into the deposition chamber 418 is stopped, and the
After continuing to flow H ₂ gas into the deposition chamber 418,
The flow of H ₂ gas was also stopped, and the inside of the deposition chamber 418 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Next, a-Si was produced in the same manner as in Example 2.
The MWi type layer 307 made of Ge was formed by the MWPCVD method. Next, hydrogen plasma treatment containing a trace amount of silane-based gas was performed under the conditions shown in Table 21 (8). To perform the hydrogen plasma treatment containing a trace amount of silane-based gas, SiH ₄ gas and H ₂ gas as silicon atom-containing gas are introduced into the deposition chamber 418 through the gas introduction pipe 449, and the H ₂ gas flow rate is 12
The valves 463, 453, and 45 are set to be 00 sccm.
0 was opened and adjusted by the mass flow controller 458. The valves 461 and 451 were opened and the mass flow controller 456 adjusted the gas containing silicon atoms to 0.03% of the H ₂ gas flow rate. The conductance valve (not shown) was adjusted so that the pressure in the deposition chamber 418 became 0.6 Torr. The substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 280 ° C., and when the substrate temperature is stabilized, the RF power source 424 is set.
Is set to 0.04 W / cm ³ and the bias rod 42
8, RF power was applied. Glow discharge was generated in the deposition chamber 418, the shutter 427 was opened, and hydrogen plasma treatment containing a trace amount of silane-based gas was performed for 3 minutes. After that, the RF power is turned off, the glow discharge is stopped, the flow of the SiH ₄ gas into the deposition chamber 418 is stopped, and the flow of the H ₂ gas into the deposition chamber 418 is continued for 3 minutes, and then the flow of the H ₂ gas is also stopped. The inside of the deposition chamber 418 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Next, a-Si was formed in the same manner as in Example 2.
P / i buffer layer 362 made of C by RFPCVD
Formed by Next, the present invention contains trace amounts of Group III elements.
Hydrogen plasma treatment was performed under the conditions shown in Table 21 (9). Departure
To perform a hydrogen plasma treatment containing a trace amount of group III elements
Is B as a group III element-containing gas._TwoH₆/ H_Two(Dilution degree:
10%) gas, SiH as a gas containing silicon atoms_FourMoth
S, H_TwoThe gas is introduced into the deposition chamber 418 by the gas introduction pipe 4.
Introduced through 49, H_TwoGas flow rate is 1500sccm
Open the valves 463, 453, 450 so that
The adjustment was performed with the sflow controller 458. Group III
Element-containing gas B_TwoH₆/ H_TwoGas is all H_TwoFor gas flow
Open valves 468 and 466 to 1.0%
It was adjusted by the flow controller 467. Silicon atom
Contained gas, all H_Two0.03% of gas flow
Open the valves 461 and 451 as shown in FIG.
The adjustment was made by the roller 456. Pressure in deposition chamber 418
Conductor (not shown) so that the force becomes 0.5 Torr
Adjusted with a valve. The temperature of the substrate 490 becomes 260 ° C.
The substrate heating heater 411 is set to
Is stable, the power of the RF power source 424 is reduced to 0.02.
W / cm ^Three, And apply RF power to the bias rod 428
Added. Glow discharge occurs in the deposition chamber 418
Open the shutter 427 for 3 minutes.
A group-element-containing hydrogen plasma treatment was performed. Then RF power
To stop the glow discharge and leave the deposition chamber 418
B to_TwoH₆/ H_Two(Dilution: 10%) Gas, SiH_Fourgas
Is stopped, and H is introduced into the deposition chamber 418 for 3 minutes._Two
After continuing the gas flow, H_TwoStop the flow of gas,
1 × 10 in chamber 418 and gas pipe^-FiveTor
e was evacuated to r. Next, a method similar to that of the second embodiment is used.
RF p-type layer 308 made of a-SiC, μc-Si
An RF n-type layer 309 made of was formed in order.

Next, hydrogen plasma treatment containing a trace amount of silane-based gas was performed under the conditions shown in Table 21 (10). In order to perform the hydrogen plasma treatment containing a trace amount of silane-based gas, a SiH ₄ / H ₂ (dilution: 1000 ppm) gas and a H ₂ gas as silicon atom-containing gas are introduced into the deposition chamber 417 by a gas introduction pipe 4.
The valves 441, 431, and 430 were opened so that the flow rate of H ₂ gas became 850 sccm, and the mass flow controller 436 adjusted the flow rate. The gas containing silicon atoms was adjusted by the mass flow controller 437 by opening the valves 442 and 432 so that the ratio of the SiH ₄ gas to the total H ₂ gas flow was 0.03%. The pressure inside the deposition chamber 417 was adjusted with a conductance valve (not shown) so as to be 0.9 Torr.

The temperature of the substrate 490 is set to 230 ° C.
Set the substrate heater 410 to ensure that the substrate temperature is stable.
Then, the power of the RF power supply 422 is set to 0.04 W / cm
^Three, RF power is introduced, and the plasma forming cup
Glow discharge is generated in 420 and a minute amount of silane
A gas-containing hydrogen plasma treatment was performed. Then turn on the RF power
Cut, stop glow discharge, and into deposition chamber 417
SiH_Four/ H_Two(Dilution: 1000 ppm) Gas inflow
Is stopped, and H is introduced into the deposition chamber 417 for 3 minutes. _TwoGas
After continuing to flow, H_TwoStops gas flow and deposits
1 × 10^-FiveUp to Torr
Evacuated.

Next, a-Si was produced in the same manner as in Example 2.
An n / i buffer layer 353 made of C was formed by RFPCVD. Next, a hydrogen plasma treatment containing a trace amount of silane-based gas was performed under the conditions shown in Table 21 (11). To perform the hydrogen plasma treatment containing a trace amount of silane-based gas, SiH ₄ gas and H ₂ gas as silicon atom-containing gas are introduced into the deposition chamber 418 through the gas introduction pipe 449 so that the H ₂ gas flow rate becomes 1000 sccm. Valve 463,
Open 453 and 450 and open the mass flow controller 45
Adjusted at 8.

The silicon atom-containing gas was supplied to the valve 4 so that the SiH ₄ gas became 0.03% of the H ₂ gas flow rate.
61 and 451 were opened and adjusted by the mass flow controller 456. The pressure in the deposition chamber 418 is 0.7 To
rr was adjusted by a conductance valve (not shown). The substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 230 ° C. When the substrate temperature is stabilized, the power of the RF power supply 424 is set to 0.03 W / cm ³ , and the RF power is supplied to the bias rod 428. Applied. Glow discharge is generated in the deposition chamber 418, and the shutter 4
27 was opened, and a hydrogen plasma treatment containing a trace amount of silane-based gas was performed for 3 minutes. Thereafter, the RF power source is turned off, the glow discharge is stopped, the flow of SiH ₄ gas into the deposition chamber 418 is stopped, and the flow of H ₂ gas into the deposition chamber 418 is continued for 3 minutes, and then the flow of H ₂ gas is also stopped. The inside of the deposition chamber 418 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Next, a-Si was produced in the same manner as in Example 2.
The RFi-type layer 310 made of was formed by the RFPCVD method. Next, hydrogen plasma treatment containing a small amount of silane-based gas was performed under the conditions shown in Table 21 (12). To perform the hydrogen plasma treatment containing a trace amount of silane-based gas, SiH ₄ gas and H ₂ gas are introduced as gas containing silicon atoms into the deposition chamber 418 through the gas introduction pipe 449, and the H ₂ gas flow rate is set to 1
The valves 463, 453, and 4 are set to 200 sccm.
50 was opened and adjusted by the mass flow controller 458. The gas containing silicon atoms is supplied to the valves 461 and 45 so that the SiH ₄ gas becomes 0.03% of the H ₂ gas flow rate.
1 was opened and adjusted by the mass flow controller 456.
The conductance valve (not shown) was adjusted so that the pressure in the deposition chamber 418 became 0.8 Torr. The substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 200 ° C., and when the substrate temperature becomes stable, the RF
The power of the power supply 424 was set to 0.04 W / cm ³ , and RF power was applied to the bias rod 428.

A glow discharge was generated in the deposition chamber 418, the shutter 427 was opened, and a hydrogen plasma treatment containing a small amount of silane-based gas was performed for 3 minutes. Thereafter, the RF power supply is turned off, the glow discharge is stopped, the flow of SiH ₄ gas into the deposition chamber 418 is stopped, and the deposition chamber 4 is stopped for 3 minutes.
After the H ₂ gas has been continuously flowed into the chamber 18, the inflow of the H ₂ gas is also stopped, and the inside of the deposition chamber 418 and the inside of the gas pipe are 1 × 1
The chamber was evacuated to 0 ^-5 Torr.

Next, a-Si was produced in the same manner as in Example 2.
A p / i buffer layer 363 made of C was formed by RFPCVD. Next, hydrogen plasma treatment containing trace amounts of Group III elements according to the present invention was performed under the conditions shown in Table 21 (13). In order to carry out the hydrogen plasma treatment containing trace amounts of group III elements according to the present invention, a B ₂ H ₆ / H ₂ (dilution: 10%) gas as a group III element-containing gas and a Si atom-containing gas as a silicon atom-containing gas are used.
H ₄ gas and H ₂ gas are introduced into the deposition chamber 418 through the gas introduction pipe 449, and the H ₂ gas flow rate is 1400 sc.
cm, the valves 463, 453, and 450 were opened and adjusted by the mass flow controller 458. II
The valves 468 and 466 were opened and the mass flow controller 467 was adjusted so that the group I element-containing gas B ₂ H ₆ / H ₂ gas became 2.0% of the total H ₂ gas flow rate. The valves 461 and 451 were opened and the mass flow controller 456 adjusted so that the silicon atom-containing gas and the SiH ₄ gas became 0.03% of the total H ₂ gas flow rate. The conductance valve (not shown) was adjusted so that the pressure in the deposition chamber 418 became 0.7 Torr. The substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 170 ° C., and when the substrate temperature is stabilized, the RF power source 424 is set.
Is set to 0.02 W / cm ³ and the bias rod 42
8, RF power was applied. By generating a glow discharge in the deposition chamber 418 and opening the shutter 427, the hydrogen plasma treatment containing a trace amount of Group III element of the present invention was performed for 3 minutes.

Thereafter, the RF power supply was turned off to stop the glow discharge, and the flow of the B ₂ H ₆ / H ₂ (dilution: 10%) gas and SiH ₄ gas into the deposition chamber 418 was stopped. After the flow of H ₂ gas was continued into 418, the flow of H ₂ gas was stopped, and the inside of the deposition chamber 418 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr. Next, an RFp type layer 311 made of a-SiC was formed by an RFPCVD method in the same manner as in Example 2. Next, as the transparent conductive layer 312, ITO having a thickness of 70 nm was vacuum-deposited on the RFp-type layer 311 by a vacuum deposition method.

Next, a mask having a comb-shaped hole is placed on the transparent conductive layer 312, and Cr (40 nm) / Ag (1000 n
m) / Cr (40 nm) comb-shaped current collecting electrode 313
Was vacuum deposited by a vacuum deposition method. Thus, the production of the solar cell has been completed. This solar cell will be referred to as (SC Ex. 21). The conditions of the hydrogen plasma treatment containing a trace amount of Group III element and the hydrogen plasma containing a trace amount of silane-based gas of the present invention, RFn
Table 21 shows the conditions for forming the mold layer, n / i buffer layer, MWi layer, p / i buffer layer, RFi layer, and RFp layer.
(1) to 21 (14) are shown.

Comparative Example 21 A solar cell (SC ratio: 21) was prepared under the same conditions as in Example 21 except that the hydrogen plasma treatment containing trace amounts of Group III elements and the hydrogen plasma treatment containing trace amounts of silane-based gas of the present invention were not performed. Produced. Solar cell (SC actual 2
1) and (SC ratio 21) were manufactured in nine pieces each, and the initial photoelectric conversion efficiency (photoelectromotive power / incident optical power), vibration degradation,
Light degradation, vibration degradation in high temperature and high humidity environment when bias voltage was applied, light degradation, and reverse bias voltage application characteristics were measured.

The initial photoelectric conversion efficiency can be obtained by installing the manufactured solar cell under AM1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristics. As a result of the measurement, the fill factor (FF) of the initial photoelectric conversion efficiency of (SC actual 21) and the series resistance (R
s) and characteristic unevenness were as follows. Fill factor Series resistance Characteristic unevenness (SC Actual 21) 1.18 times 0.88 times 0.80 times For the measurement of vibration deterioration, a solar cell whose initial photoelectric conversion efficiency was measured in advance was measured at a humidity of 56% and a temperature of 26 ° C. In a dark place with a vibration frequency of 60 Hz and an amplitude of 0.1 mm.
AM1.5 (100 mW / cm ² ) after adding for 0 hours
The measurement was performed based on the rate of decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after vibration degradation test / initial photoelectric conversion efficiency). The photodegradation was measured by installing a solar cell whose initial photoelectric conversion efficiency was measured in advance in an environment with a humidity of 56% and a temperature of 26 ° C.
1.5 (100 mW / cm ²⁾ light and after irradiation for 500 hours, AM1.5 (100mW / cm ²⁾ photoelectric conversion efficiency / initial photoelectric conversion efficiency after decrease rate of photoelectric conversion efficiency (light degradation test under irradiation ).

As a result of the measurement, (S
The rate of decrease in photoelectric conversion efficiency after photodeterioration of C ratio 21) and the rate of decrease in photoelectric conversion efficiency after vibration degradation were as follows. Vibration degradation and light degradation in a high temperature and high humidity environment at the time of bias application were measured. Two solar cells whose initial photoelectric conversion efficiencies were measured in advance were placed in a dark place with a humidity of 93% and a temperature of 82 ° C., and 0.71 V was applied as a forward bias voltage. The above-mentioned vibration was applied to one of the solar cells, and the deterioration of the vibration was measured.
Was irradiated to measure the photodegradation.

As a result of the measurement, (SC actual 21)
The reduction rate of the photoelectric conversion efficiency after vibration deterioration (SC ratio 21) and the reduction rate of the photoelectric conversion efficiency after light deterioration were as follows. The measurement of the reverse bias voltage application characteristic is performed by measuring the initial photoelectric conversion efficiency of a solar cell at a humidity of 52% and a temperature of 8%.
It was installed in a dark place at 0 ° C., and the reverse bias voltage was 5.0 V,
After applying for 100 hours, AM1.5 (100 mW / cm
² ) The photoelectric conversion efficiency under irradiation was measured, and the reduction rate (photoelectric conversion efficiency after application of reverse bias voltage / initial photoelectric conversion efficiency) was used.

As a result of the measurement, (SC actual 21)
The decrease rate of the (SC ratio 21) after application of the reverse bias voltage was as follows. (SC ratio 21) 0.84 times The state of delamination was observed using an optical microscope. In (SC Ex 21), no delamination was observed, but (SC ratio 21)
In, slight delamination was observed. As described above, the solar cell (SC actual 21) of the present invention is different from the conventional solar cell (SC ratio 2).
Fill factor in photoelectric conversion efficiency of solar cell than 1),
It was found that the series resistance, the characteristic unevenness, the light deterioration characteristic, the adhesion, the durability, and the reverse bias voltage application characteristic were more excellent.

In the above embodiments, the n-type layer and the n /
The description has been given of the solar cell in which the i-buffer layer, the i-type layer, the p / i buffer layer, and the p-type layer are stacked in this order, but the p-type layer, the p / i buffer layer, the i-type layer, and the n / i buffer layer are provided on the substrate. The same hydrogen plasma treatment was performed on solar cells stacked in this order on the n-type layer to produce solar cells. When the same evaluation as in the above example was performed, a gas containing silicon atoms and a gas in the periodic table were placed between the p / i buffer layer and the p-type layer.
Solar cells plasma-treated with hydrogen gas containing Group III element-containing gas have excellent characteristics such as fill factor in photoelectric conversion efficiency, characteristic unevenness, light degradation characteristics, series resistance characteristics, durability, and reverse bias voltage application characteristics The thing was confirmed. In addition, the vicinity of the interface between the substrate and the p-type layer, the vicinity of the interface between the n / i buffer layer and the n-type layer, the vicinity of the interface between the n / i buffer layer and the i-type layer, and the vicinity of the p / i buffer layer and i It has been found that the above characteristics are further improved by performing a plasma treatment on the vicinity of the interface in contact with the mold layer with a hydrogen gas containing a silicon atom-containing gas to such an extent that substantially no deposition occurs.

[0208]

[Table 1 (1)]

[0209]

[Table 1 (2)]

[0210]

[Table 2 (1)]

[0211]

[Table 2 (2)]

[0212]

[Table 2 (3)]

[0213]

[Table 3 (1)]

[0214]

[Table 3 (2)]

[0215]

[Table 3 (3)]

[0216]

[Table 3 (4)]

[0219]

[Table 4 (1)]

[0218]

[Table 4 (2)]

[0219]

[Table 4 (3)]

[0220]

[Table 5 (1)]

[0221]

[Table 5 (2)]

[0222]

[Table 5 (3)]

[0223]

[Table 6 (1)]

[0224]

[Table 6 (2)]

[0225]

[Table 6 (3)]

[0226]

[Table 7 (1)]

[0227]

[Table 7 (2)]

[0228]

[Table 7 (3)]

[0229]

[Table 8 (1)]

[0230]

[Table 8 (2)]

[0231]

[Table 8 (3)]

[0232]

[Table 9 (1)]

[0233]

[Table 9 (2)]

[0234]

[Table 9 (3)]

[0235]

[Table 10 (1)]

[0236]

[Table 10 (2)]

[0237]

[Table 10 (3)]

[0238]

[Table 11 (1)]

[0239]

[Table 11 (2)]

[0240]

[Table 11 (3)]

[0241]

[Table 12 (1)]

[0242]

[Table 12 (2)]

[0243]

[Table 12 (3)]

[0244]

[Table 13 (1)]

[0245]

[Table 13 (2)]

[0246]

[Table 13 (3)]

[0247]

[Table 14 (1)]

[0248]

[Table 14 (2)]

[0249]

[Table 14 (3)]

[0250]

[Table 15 (1)]

[0251]

[Table 15 (2)]

[0252]

[Table 15 (3)]

[0253]

[Table 16 (1)]

[0254]

[Table 16 (2)]

[0255]

[Table 16 (3)]

[0256]

[Table 17 (1)]

[0257]

[Table 17 (2)]

[0258]

[Table 17 (3)]

[0259]

[Table 18 (1)]

[0260]

[Table 18 (2)]

[0261]

[Table 18 (3)]

[0262]

[Table 19 (1)]

[0263]

[Table 19 (2)]

[0264]

[Table 19 (3)]

[0265]

[Table 20 (1)]

[0266]

[Table 20 (2)]

[0267]

[Table 20 (3)]

[0268]

[Table 21 (1)]

[0269]

[Table 21 (2)]

[0270]

[Table 21 (3)]

[0271]

[Table 21 (4)]

[0272]

[Table 21 (5)]

[0273]

[Table 21 (6)]

[0274]

[Table 21 (7)]

[0275]

[Table 21 (8)]

[0276]

[Table 21 (9)]

[0277]

[Table 21 (10)]

[0278]

[Table 21 (11)]

[0279]

[Table 21 (12)]

[0280]

[Table 21 (13)]

[0281]

[Table 21 (14)]

[0282]

According to the present invention, impurities (for example, oxygen, nitrogen, carbon, iron, chromium, etc.) which become defect levels when taken into a semiconductor layer adsorbed on or contained in a deposition chamber wall usually observed in a hydrogen plasma treatment. , Nickel, aluminum, etc.) can be solved. In addition, stable hydrogen plasma processing can be performed. As a result, 1) it is possible to provide a photovoltaic element having substantially no peeling of the semiconductor layer when the photovoltaic element is placed at high temperature and high humidity.

2) When a pin structure is formed on a flexible substrate, it is possible to provide a photovoltaic element in which a pin semiconductor layer is hardly peeled off even when the substrate is bent. 3) It is possible to provide a photovoltaic element in which an increase in defect levels near the interface between the substrate and the semiconductor layer is suppressed by long-time light irradiation. 4) Even when light is irradiated under high temperature and high humidity, it is possible to provide a photovoltaic element in which the substrate and the semiconductor layer do not peel off, and a decrease in characteristics such as an increase in series resistance is suppressed.

5) It is possible to provide a photovoltaic element having improved initial efficiency by preventing diffusion of impurities from the p-type layer (n-type layer) to the i-type layer. 6) Even when used at a high temperature, it is possible to provide a photovoltaic element with less deterioration in characteristics. 7) It is possible to provide a photovoltaic element that is hard to break when a reverse bias is applied to the photovoltaic element.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a photovoltaic element to which a method for forming a photovoltaic element according to the present invention is applied.

FIG. 2 is a schematic explanatory view of another photovoltaic element to which the method for forming a photovoltaic element of the present invention is applied.

FIG. 3 is a schematic explanatory view of another photovoltaic element to which the method of forming a photovoltaic element according to the present invention is applied.

FIG. 4 is a schematic explanatory view of a photovoltaic element forming apparatus suitable for the photovoltaic element forming method of the present invention.

[Explanation of symbols]

100, 200, 300 Support, 101, 201, 301 Reflective layer (or transparent conductive layer), 102, 202, 302 Reflection increasing layer (or antireflective layer), 103, 203, 303 First n-type layer (or 104, 204, 304 First i-type layer, 105, 205, 305 First p-type layer (or n-type layer), 112, 212, 312 Transparent conductive layer (or conductive layer), 113 , 213, 313 collecting electrode, 151, 251, 351 first n / i buffer layer, 161, 261, 361 i th p / i buffer layer, 206, 306 second n-type layer (or p-type layer) ), 207,307 second i-type layer, 208,308 second p-type layer (or n-type layer), 252,352 second n / i buffer layer, 262,362 second p / i buffer layer 309 3rd n (or p-type layer), 311 3rd p-type layer (or n-type layer), 310 3rd i-type layer, 353 3rd n / i buffer layer, 363 3rd p / i buffer layer, 400 forming apparatus, 401 load chamber, 402, 403, 404 transfer chamber, 405 unload chamber, 406, 407, 408, 409 gate valve, 410, 411, 412 substrate heating heater, 413 substrate transfer Rail, 417 n-type (or p-type) layer deposition chamber, 418 i-type layer deposition chamber, 419 p-type (or n-type) layer deposition chamber, 420,421 cup for plasma formation, 422,423,424 power supply , 425 Microwave introduction window, 426 Waveguide, 427 Shutter, 428 Bias rod, 429, 449 469 gas inlet tube, 430,431,432,433,434,441,4
42,443,444,450,451,452,4
53,454,455,461,462,463,4
64,465,468,466,470,471,47
2,473,474,481,482,483,48
4 valves, 436, 437, 438, 439, 456, 457, 4
58, 459, 460, 467, 476, 477, 4
78,479 Mass flow controller, 490 Substrate holder.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-177372 (JP, A) JP-A-3-136380 (JP, A) JP-A-1-103829 (JP, A) JP-A-2- 177375 (JP, A) JP-A-2-177376 (JP, A) JP-A-58-64070 (JP, A) JP-A-3-200374 (JP, A) JP-A-2-177371 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 31/04-31/078 H01L 21/205

Claims (5)

(57) [Claims] 1. A non-single-crystal n-type layer (or p-type layer) containing silicon atoms, a non-single-crystal i-type n / i buffer layer (or p / i buffer layer), a non-single crystal i
Layer, non-single-crystal i-type p / i buffer layer (or n /
i-buffer layer) and non-single-crystal p-type layer (or n-type layer)
In a method of manufacturing a photovoltaic element in which at least one or more pin structures formed by laminating are stacked, the vicinity of an interface where the p / i buffer layer and the p-type layer are in contact with each other is substantially non-deposited. Contained gases and Periodic Table II
A method for producing a photovoltaic element, comprising plasma-treating with a hydrogen gas containing a group I element-containing gas. 2. A plasma process is performed on the vicinity of the interface between the substrate and the n-type layer (or the vicinity of the interface between the substrate and the p-type layer) with a hydrogen gas containing a gas containing silicon atoms to such an extent that substantially no deposition occurs. The method for manufacturing a photovoltaic device according to claim 1, wherein: 3. The vicinity of an interface between the n / i buffer layer and the n-type layer, a vicinity of an interface between the n / i buffer layer and the i-type layer, and a contact between the p / i buffer layer and the i-type layer. 3. The method for manufacturing a photovoltaic device according to claim 1, wherein the vicinity of the interface is plasma-treated with a hydrogen gas containing a silicon atom-containing gas to such an extent that substantially no deposition occurs. 4. The method according to claim 1, wherein the silicon atom-containing gas is Si gas.
H ₄ , Si ₂ H ₆ , SiF ₄ , SiFH ₃ , SiF ₂ H ₂ , S
_{iF 3 H, SiCl 2 H 2} , SiCl 3 H, of the SiCl _4, claim, characterized in that it comprises at least one 1
4. The method for producing a photovoltaic device according to any one of items 3 to 5. 5. The photovoltaic device according to claim 1, wherein the content of the silicon atom-containing gas with respect to hydrogen gas is 0.1% or less .
Construction method .