JPH0992855A - Photovoltaic element forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of forming a photovoltaic element having a high reverse bias resistance whereby the optical deterioration due to the interface level is reduced and peel between semiconductor layers can be prevented. SOLUTION: A method of forming a photovoltaic element having one or more pin structured units repeatedly disposed on a substrate 190 is provided. Each unit is composed of an n-, i- and p-type semiconductor layers 103-105 laminated one above another. Each semiconductor layer has a non-single crystal structure and contains Si atoms. At least one of the surfaces of these semiconductor layers is annealed in a H gas, He gas or Ar gas atmosphere contg. an O atom-containing gas 1-1000ppm. It is preferable that the annealing temp. is 50-400 deg.C, the annealing pressure is 0.01-10Torr and the frequency of a microwave used for the microwave plasma CVD method is 0.1-10GHz.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for forming a photovoltaic device. More specifically, the present invention relates to a method for forming a photovoltaic element in which photodegradation due to an interface state is reduced, peeling between semiconductor layers can be prevented, and reverse bias resistance is high.

[0002]

2. Description of the Related Art Defect levels existing in a semiconductor layer constituting a photovoltaic element are closely related to generation and recombination of charges, and are one of the factors that influence the characteristics of the photovoltaic element. Is one.

Conventionally, the following hydrogen plasma treatment has been proposed as a method for compensating for such defect levels. (1) USP 4113514 (JI Pankove et al., RC
Company A Sep. 12, 1978) describes the completed semiconductor device,
Hydrogen plasma treatment is described. (2) “EFFECT OF PLASMA TREATMENT OF THE TCO ON a
-Si SOLAR CELL PERFORMANCE "F. Demichelis et. Al.
In Mat. Res. Soc. Symp. Proc. Vol. 258, p905, 1992, a transparent electrode deposited on a substrate was treated with hydrogen plasma,
A method of forming a pin structure solar cell thereon is disclosed. (3) “HYDROGEN-PLASMA REACTION FLUSHING FOR aS
i: H PIN SOLAR CELL FABRlCATION "YS Tsuo et. a
l. Mat. Res. Soc. Symp. Proc. Vol. 149, p471,1989
Describes that, when a solar cell having a pin structure is manufactured, the surface of the p layer is treated with hydrogen plasma before the deposition of the i layer.

In such hydrogen plasma treatment,
Only hydrogen gas is introduced into the chamber, and high frequency (hereinafter "R
The hydrogen plasma treatment was performed by activating the hydrogen gas with power.

However, the above-mentioned hydrogen plasma is
It acts on the substrate to be processed, the unfinished device, and the completed device, and spreads over the entire inner wall of the chamber.
Since hydrogen plasma is very active, substances adsorbed on or contained in the wall surface are knocked out from the inner wall surface of the chamber. As a result, if the knocked-out substance is an impurity (for example, oxygen, nitrogen, carbon, iron, chromium, nickel, aluminum, etc.) that becomes a defect level when incorporated into the semiconductor layer, There is a problem in that the generation and recombination are disturbed and the photoelectric conversion characteristics are deteriorated.

Further, hydrogen gas is more difficult to generate an electric discharge than other gases, and plasma using only hydrogen gas is more difficult to maintain the plasma than other gases, so that stable hydrogen plasma treatment can be performed. There was also the problem that it could not be done.

[0007]

DISCLOSURE OF THE INVENTION The present invention does not introduce impurities adsorbed or contained in the chamber inner wall surface into the inside of the semiconductor layer and the interface during the plasma treatment, and the plasma treatment is performed. It is an object of the present invention to provide a method for forming a photovoltaic device having high discharge stability.

[0008]

A method of forming a photovoltaic element according to the present invention comprises an n-type, i-type and p-type semiconductor layer containing a silicon atom and having a non-single crystal structure. In a method for forming a photovoltaic device, wherein a stacked pin structure is repeatedly arranged on a substrate at least once, in at least one surface of each of the semiconductor layers, an oxygen atom-containing gas is used. An annealing treatment is performed in an atmosphere of hydrogen gas, helium gas, or argon gas containing 1 to 1000 ppm.

The temperature of the annealing treatment is 50 ° C. to 4 ° C.
And the pressure of the annealing treatment is 0.01.
Torr to 10 Torr is preferable.

It is desirable that the microwave used in the microwave plasma CVD method has a frequency of 0.1 to 10 GHz.

[0011]

[Action]

(Claim 1) The present inventor believes that the surface of the semiconductor layer immediately after being deposited by the plasma CVD method has a problem from the following viewpoints. (A) The surface of the semiconductor layer immediately after being deposited by the plasma CVD method has many dangling bonds and has a structural distortion, and is very active. (B) If the next layer is laminated by leaving it in the state of (a) above, an extremely large number of interface states will remain between the previous layer and the next layer, and the electrical and mechanical characteristics of the photovoltaic device will be reduced. Cause decline. (C) The dangling bonds of the front layer and the distortion of the structure affect the deposition of the next layer, which causes abnormal growth of the next layer.

According to the first aspect of the invention, as a method for solving these problems, at least one of the surfaces of the semiconductor layer contains 1 to 1000 pp of oxygen atom-containing gas.
Annealing treatment was performed in an atmosphere of hydrogen gas, helium gas, or argon gas containing m. As a result, the oxidation rate can be controlled. If the amount of the oxygen atom-containing gas added is too large, the oxidation of the silicon layer will proceed too much, degrading the characteristics of the photovoltaic element. On the other hand, if the amount of the oxygen atom-containing gas added is too small, the effect of the present invention is difficult to obtain.

Further, the present inventor has judged that the following effects are obtained. (1) Oxygen atoms have two orientations, so that when they are bonded to silicon atoms, structural flexibility increases, which can reduce the interface state.

(2) Since oxygen atoms have a large binding energy with silicon atoms, if the annealing treatment is performed in the presence of a large amount of oxygen atoms, the silicon surface may be excessively oxidized and may be insulated. As described above, when the annealing treatment is performed in a controlled state in which the oxygen atom content is small, it is possible to treat the surface of several atomic layers or less of the silicon surface.

(3) As described in (1) and (2) above, when a next layer is laminated on the silicon surface which has been surface-treated with an oxygen atom-containing gas, surface defects and structural distortion are reduced. In addition, a deposited film having very few defect levels can be formed in the next layer, and a uniform film having no columnar structure can be formed in the next layer.

(4) Oxygen atoms combine with silicon atoms to form silicon oxide, and the silicon oxide layer has a bandgap wider than that of a layer made of silicon atoms. growing.

(5) In the silicon oxide layer as described in (1) to (4) above, since the positions of the conduction band and the valence band are wider than those of the layer made of silicon atoms, that is, the electron affinity. Gradients and ionization energy gradients are formed,
Charges photoexcited in the vicinity of the silicon oxide layer can be efficiently separated without recombination. As a result, the photocurrent of the photovoltaic element increases. In particular, when the light is irradiated from the silicon oxide layer side, the utilization efficiency of the light on the short wavelength side is improved. In addition, the photodegradation associated with the interface state is reduced.

(6) When an oxygen atom is bonded to a silicon atom, it has a large electronegativity and thus is negatively charged. As a result, the adhesion with the next layer is improved. In particular, peeling of the semiconductor layer when the photovoltaic element is placed at high temperature and high humidity can be reduced. Further, even when the photovoltaic element is bent, peeling between semiconductor layers can be prevented.

(7) By forming the silicon oxide layer, when a p-type layer or an n-type layer is deposited on the next layer, diffusion of impurities from the next layer can be prevented. Especially, when the photovoltaic element is used at a high temperature, the deterioration of the characteristics is small.

(8) Since the extremely thin silicon oxide layer is present near the interface between the i-type layer and the p-type layer or the n-type layer of the photovoltaic element, the silicon oxide layer has a wide band gap, and When the reverse bias is applied to the power element, it is less likely to break.

As for the addition amount of the oxygen atom-containing gas, it is preferable to reduce the addition amount of the active gas such as oxygen gas and perform the annealing treatment. It is preferable to add a relatively large amount of a relatively inert gas such as CO ₂ .

Further, as a method of introducing the hydrogen gas, the helium gas or the argon gas to which the oxygen element-containing gas is added, it is preferable to introduce the hydrogen gas by spraying on the silicon semiconductor layer. It is considered that the introduction in this way makes it possible to uniformly treat the surface of the silicon semiconductor.

(Claim 2) In the invention according to claim 2, the temperature of the annealing treatment is 50 ° C to 400 ° C. As a result, the silicon layer can be oxidized by an appropriate thickness. At temperatures lower than 50 ° C, it is difficult to oxidize. Further, at a temperature higher than 400 ° C., the surface of the silicon layer is excessively oxidized and becomes insulating. Further, the photovoltaic element itself may be destroyed. Therefore, the oxidation of the surface of the silicon layer can be controlled only when the temperature of the annealing treatment is 50 ° C to 400 ° C.

When the annealing treatment of the present invention is carried out by adding an active oxygen atom-containing gas, it is preferable to perform the treatment at a relatively low temperature. Further, when the annealing treatment of the present invention is carried out by adding a relatively inert oxygen atom-containing gas, it is preferable to carry out the annealing treatment at a relatively high temperature. It is also preferable to perform the annealing treatment of the present invention while changing the temperature. Regarding the temperature distribution during the annealing treatment of the present invention, it is desirable to perform the treatment at a relatively high temperature immediately after depositing the silicon semiconductor layer to be treated and to gradually lower the temperature.

(Claim 3) In the invention according to claim 3, the pressure of the annealing treatment is 0.01 Torr to 10 Tor.
r. As a result, the silicon layer can be oxidized by an appropriate thickness. At a pressure lower than 0.01 Torr, it is difficult to oxidize. Further, at a pressure higher than 10 Torr, the surface of the silicon layer is excessively oxidized and becomes insulating. In addition, the photovoltaic element itself may be destroyed. Therefore, the pressure of the annealing process should be 0.
Only when the pressure is from 01 Torr to 10 Torr, the oxidation of the surface of the silicon layer can be controlled.

In particular, when the roll-to-roll method is used, it is preferable to set the pressure so that the pressure becomes low on the side of the film formation space of the semiconductor layer.

(Fourth aspect) In the invention according to the fourth aspect, since the frequency of the microwave used in the microwave plasma CVD method is set to 0.1 to 10 GHz, the raw material gases having different decomposition energies are efficiently produced at a low pressure. It can be decomposed well, and as a result, high-speed film formation becomes possible. Therefore, by performing the annealing treatment of the present invention on the deposited film in the microwave frequency region, the structural relaxation of the surface of the silicon layer is further advanced, and the photodegradation related to the interface state can be suppressed.

[0028]

[Example embodiment]

(Photovoltaic Element) Examples of the photovoltaic element formed by performing the annealing treatment in the present invention include those shown in FIGS. 1 to 3. 1, 2 and 3 are respectively 1
It shows the case of having three pin structures, the case of having two pin structures, and the case of having three pin structures. Hereinafter, description will be made with reference to FIGS. 1 to 3.

FIG. 1 is a schematic explanatory view of a photovoltaic element having one pin structure. As the photovoltaic element,
There are two cases: irradiation with light from the side opposite to the substrate and irradiation with light from the side of the substrate.

When the light is irradiated from the side opposite to the substrate, the substrate 190 composed of the support 100, the reflective layer 101, and the reflection increasing layer 102 and the first n-type layer (or p) in this order from the bottom.
Mold layer) 103, n / i (or p / i) buffer layer 1
51, first i-type layer 104, p / i (or n / i) buffer layer 161, first p-type layer (or n-type layer) 10
5, a transparent electrode 112, and a collector electrode 113.

When irradiating light from the substrate side, 1
00 is a transparent support, 101 is a transparent conductive layer, and 10 is a transparent conductive layer.
2 is replaced with an antireflection layer, and 112 is replaced with a conductive layer also serving as a reflection layer.

FIG. 2 is a schematic explanatory view of a photovoltaic element having two pin structures. As the photovoltaic element,
There are two cases: irradiation with light from the side opposite to the substrate and irradiation with light from the side of the substrate.

When irradiating light from the side opposite to the substrate, the substrate 290 comprising the support 200, the reflective layer 201, and the reflection increasing layer 202 and the first n-type layer (or p) in this order from the bottom.
Mold layer) 203, n / i (or p / i) buffer layer 2
51, first i-type layer 204, p / i (or n / i) buffer layer 261, first p-type layer (or n-type layer) 20
5, a second n-type layer (or p-type layer) 206, a second i-type layer 207, a second p-type layer (or n-type layer) 208, a transparent electrode 212, and a collector electrode 213. There is.

When irradiating light from the substrate side, 2
00 to the transparent support, 201 to the transparent conductive layer, 20
2 is replaced with an antireflection layer, and 212 is replaced with a conductive layer also serving as a reflection layer.

FIG. 3 is a schematic explanatory view of a photovoltaic device having three pin structures. As the photovoltaic element,
There are two cases: irradiation with light from the side opposite to the substrate and irradiation with light from the side of the substrate.

When the light is irradiated from the side opposite to the substrate, the substrate 390 including the support 300, the reflective layer 301, and the reflection increasing layer 302 and the first n-type layer (or p-type) in this order from the bottom.
Type layer) 303, first n / i (or p / i) buffer layer 351, first i-type layer 304, first p / i (or n / i) buffer layer 361, first p-type Layer (or n-type layer) 305, second n-type layer (or p-type layer) 30
6, second n / i (or p / i) buffer layer 35
2, second i-type layer 307, second p / i (or n /
i) buffer layer 362, second p-type layer (or n-type layer) 308, third n-type layer (or p-type layer) 309, third i-type layer 310, third p-type layer (or n-type layer) 31
1, a transparent electrode 312, and a collector electrode 313.

In case of irradiating light from the substrate side, 3
00 is a transparent support, 301 is a transparent conductive layer, and 30
2 is replaced with an antireflection layer, and 312 is replaced with a conductive layer also serving as a reflection layer.

(Annealing Treatment) The annealing treatment in the present invention is performed, for example, near the interface between the p / i buffer layer and the p-type layer, near the interface between the n / i buffer layer and the n layer, or between the i layer and the p layer. And near the interface with the n-layer is effective. The flow rate of hydrogen gas, helium gas, or argon gas suitable for achieving the object of the present invention is appropriately optimized depending on the size of the processing chamber, but is preferably 100 to 10,000 sccm.

(Apparatus and method for forming photovoltaic element)
Examples of the forming apparatus in the present invention include those shown in FIGS. 4 and 5. FIG. 4 shows an in-line type forming device,
FIG. 5 is a schematic sectional view showing an example of a roll-to-roll type forming apparatus.

The in-line forming apparatus shown in FIG. 4 will be described below. The forming apparatus 400 includes a load chamber 401, transfer chambers 402, 403, 4 and
04, unload chamber 405, gate valve 40
6, 407, 408, 409, substrate heating heater 41
0, 411, 412, a substrate transfer rail 413, an n-type layer (or p-type layer) deposition chamber 417, an i-type layer deposition chamber 418, a p-type layer (or n-type layer) deposition chamber 419, a plasma forming cup 420. , 421, power sources 422, 423, 424, microwave introduction window 425,
Waveguide 426, gas introduction pipes 429, 449, 469, valves 430, 431, 432, 433, 434, 44.
1, 442, 443, 444, 450, 451, 45
2,453,454,455,461,462,46
3, 464, 465, 470, 471, 472, 47
3, 474, 481, 482, 483, 484, mass flow controllers 436, 437, 438, 439,
456, 457, 458, 459, 460, 476, 4
77, 478, 479, 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 controller (not shown), and the like.

A method of forming a photovoltaic element using the in-line type forming apparatus shown in FIG. 4 will be described below. Numbers in parentheses indicate formation procedure. (1) All the chambers of the deposition apparatus 400 are connected to the respective chambers by turbo molecular pumps (not shown) at 10 ^−6.
Evacuate to a vacuum below Torr.

(2) A substrate on which a reflective layer of silver or the like is vapor-deposited on a stainless steel support and a reflection-increasing layer of zinc oxide or the like is vapor-deposited is attached to the substrate holder 490. (3) Put the substrate holder 490 in the load chamber 401. The door of the load chamber 401 is closed, and the load chamber 401 is evacuated to a predetermined vacuum degree by a mechanical booster pump / rotary pump (MP / RP) not shown.

(4) When the load chamber reaches a predetermined vacuum degree, the MP / RP is switched to a turbo molecular pump and the load chamber is evacuated to a vacuum degree of 10 ^-6 Torr or less. (5) When the load chamber reaches a vacuum degree of 10 ⁻⁶ Torr or less, the gate valve 406 is opened, the substrate holder 490 on the substrate transfer rail 413 is moved to the transfer chamber 402, and the gate valve 406 is closed.

(6) The heater 410 for heating the substrate in the transfer chamber 402 is raised so that the substrate holder 490 does not hit it. Position the substrate holder so that the substrate is directly under the heater. The heater 410 for heating the substrate is lowered, and the substrate is placed in the n-type layer deposition chamber.

(7) The substrate temperature is changed to a temperature suitable for depositing the n-type layer, and the silicon atom-containing gas such as SiH ₄ and Si ₂ H ₆ for depositing the n-type layer and the periodic rule for depositing the n-type layer. A gas containing a group V element in the table is passed through a valve 433, a mass flow controller 438, and a valve 433 to deposit a chamber 417
To be introduced. Further, it is preferable that the flow rate of hydrogen gas is also appropriately adjusted according to the n-type layer. In this way, the source gas for n-type layer deposition is introduced into the deposition chamber 417,
The opening / closing degree of an exhaust valve (not shown) is changed to deposit chamber 417.
The inside is made a desired vacuum degree of 0.1 to 10 Torr.

(8) RF power is introduced from the RF power supply 422 to the plasma forming cup 420 to cause plasma discharge and maintain discharge for a desired time. In this way, an n-type semiconductor layer is deposited on the substrate to a desired thickness.

(9) 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 inside of the deposition chamber is depressurized to 10 ⁻⁶ Torr by a turbo molecular pump.

(10) The gate valve 407 is opened, the substrate holder 490 is moved to the transfer chamber 403, and the gate valve 407 is closed. (11) Adjust the substrate holder position 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 hydrogen gas or helium gas is introduced into the deposition chamber 418. The degree of vacuum at that time is n /
It is preferable to carry out at the same degree of vacuum as when depositing the i buffer layer.

(12) When the substrate temperature reaches the desired temperature, the gas for heating the substrate is stopped and the source gas for n / i buffer layer deposition is supplied from the gas supply device to the deposition chamber 41.
Supply to 8. For example, hydrogen gas, silane gas, and germane gas are opened by opening valves 462, 463, and 464, respectively, and mass flow controllers 457, 458, and 459.
And set the desired flow rate with the valves 452, 453, 454,
After opening 450, the gas is supplied to the deposition chamber 418 through the gas introduction pipe 449. At the same time, the supply gas is evacuated by a diffusion pump (not shown) so that the vacuum degree of the deposition chamber 418 becomes a desired pressure.

(13) When the degree of vacuum in the chamber 418 stabilizes at the desired degree of vacuum, the desired power is introduced from the RF power source (not shown) to the bias rod for bias application. Then, an n / i buffer layer is deposited by the RF plasma CVD method. The n / i buffer layer is preferably deposited at a slower deposition rate than the i-type layer deposited thereafter.

(14) The substrate temperature is heated to a predetermined temperature for i-type layer deposition. It is preferable that the valve 461 be opened with an inert gas such as hydrogen gas or helium gas, the mass flow controller be set to a desired flow rate, and the valves 451 and 450 be opened to allow the substrate to be heated.
The vacuum degree at that time is preferably the same as the vacuum degree when depositing the i-type layer.

(15) 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 from the gas supply device to the deposition chamber 418. For example, hydrogen gas, silane gas, and germane gas are opened with valves 462, 463, and 464, respectively, a desired flow rate is set by mass flow controllers 457, 458, and 459, and valves 452, 453, 454, and 450 are opened, and gas introduction pipe 449 is opened. Through the deposition chamber 418. At the same time, the supply gas is evacuated by a diffusion pump (not shown) so that the vacuum degree of the deposition chamber 418 becomes a desired pressure.

(16) If the degree of vacuum in the chamber 418 is stabilized at the desired degree of vacuum, a desired power is supplied from a microwave power source (not shown) to the waveguide 426 and the microwave introduction window 42.
5 into the deposition chamber 418. Simultaneously with the introduction of microwave energy, it is also preferable to introduce a desired bias power into the deposition chamber 418 from an external DC, RF or VHF power supply 424 to the biasing bias rod as shown in an enlarged view of the deposition chamber 418. It is a thing. In this way, the i-type layer is deposited to a desired layer thickness. When the i-type layer has been deposited to a desired layer thickness, the microwave power and bias are stopped.

(17) If necessary, the deposition chamber 41
The inside of 8 is purged with an inert gas such as hydrogen gas or helium gas. Then, the p / i buffer layer is deposited to a desired layer thickness in the same manner as the n / i buffer layer is deposited.
Then, if necessary, the inside of the deposition chamber 418 is purged with an inert gas such as hydrogen gas or helium gas.

(18) The annealing treatment of the present invention on the p / i type layer is performed as follows. After changing the cylinder or the like to the raw material gas required for the annealing of the present invention and sufficiently purging the gas line, the hydrogen gas and the oxygen atom-containing gas necessary for performing the annealing treatment of the present invention in the chamber are supplied with valves 461 and 462. A predetermined flow rate is introduced into the deposition chamber 418 via the mass flow controllers 456, 457, the valves 451, 452, and the valve 450. The degree of opening and closing of an exhaust valve (not shown) is changed to bring the inside of the deposition chamber 418 to a desired degree of vacuum. In this way, the annealing treatment of the present invention is performed for a predetermined time.

It is desirable to appropriately change the flow rate of the hydrogen gas, the flow rate of the oxygen atom-containing gas, the substrate temperature, etc. during the annealing treatment depending on the front condition of the substrate and the condition of the inner wall of the chamber. The preferred mode of variation of these parameters is initially to increase the hydrogen flow rate and decrease the hydrogen flow rate over time. As a form of change in the flow rate of the oxygen atom-containing gas, the flow rate of the oxygen atom-containing gas is initially small and the flow rate of the oxygen atom-containing gas increases with time.

(19) After the above annealing process is completed, the inside of the deposition chamber is purged, the exhaust gas is changed from the diffusion pump to the turbo molecular pump, and the degree of vacuum in the deposition chamber is set to 1
The degree of vacuum is set to 0 ^-6 Torr or less. At the same time, raise the heater for heating the substrate so that the substrate holder can move. The gate valve 408 is opened, the substrate holder is moved from the transfer chamber 403 to the transfer chamber 404,
The gate valve 408 is closed.

(20) The substrate holder is moved right below the substrate heating heater 412, and the substrate is heated by the substrate heating heater 412. Exhaust from MP / MP
In place of RP, it is a more preferable form to heat the substrate by flowing an inert gas such as hydrogen gas or helium gas at the time of heating so as to have the pressure at the time of depositing the p-type layer. When the substrate temperature stabilizes at the desired substrate temperature, the supply of the substrate heating gas such as the substrate heating hydrogen gas or the inert gas is stopped, and p
As a source gas for depositing the mold layer, H ₂ and SiH ₄ are used. For a p-type layer, a Group III element-containing gas of the periodic table such as BF ₃ is opened in valves 482, 483 and 484, and mass flow controllers 477 and 478 are used. Further, valves 472, 473, 474 are opened via 479 to supply a desired flow rate to the deposition chamber 419 through the gas introduction pipe 469.

(21) The exhaust valve is adjusted so that the internal pressure of the deposition chamber 419 reaches a desired vacuum level, and after stabilizing at the desired vacuum level, the RF power source 423 supplies RF power to the plasma forming cup. Then, the p-type layer is deposited by depositing for a desired time.

(22) After the deposition, the RF power and the supply of the source gas are stopped and the inside of the deposition chamber is sufficiently purged with an inert gas such as hydrogen gas or helium gas. After completion of the purging, the exhaust gas is replaced with a turbo molecular pump from the MP / RP and exhausted to a vacuum degree of 10 ^-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 405. The gate valve 409 is closed, and when the temperature of the substrate holder becomes 100 ° C. or lower, the door of the unload chamber is opened and the substrate is taken out. By the above-mentioned process, pi is formed on the substrate subjected to the annealing treatment of the present invention.
An n semiconductor layer is formed.

(23) The substrate on which the pin semiconductor layer is formed is set in a vacuum vapor deposition device for depositing a transparent electrode to form a transparent electrode on the semiconductor layer. Further, the substrate on which the transparent electrode is formed is set in a vacuum vapor deposition device for depositing the collecting electrode, and the collecting electrode is deposited. The photovoltaic element of the present invention is formed by the steps (1) to (23) described above.

It is also preferable to carry out the annealing treatment of the present invention near the interface between the substrate and the n-type layer. In order to perform the annealing treatment on the vicinity of 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 procedure, and the substrate is kept at a predetermined substrate temperature. In the procedure, the oxygen atom-containing gas and the hydrogen gas are introduced into the deposition chamber at a predetermined flow rate. Adjust the pressure with the pressure control valve so that the vacuum is suitable. The annealing treatment of the present invention is performed on the substrate for a predetermined time.

Further, the characteristics of the photovoltaic element are further improved by performing the annealing treatment of the present invention even in the vicinity of the interface between the n / i buffer layer and the i-type layer. The annealing treatment of the present invention is performed as follows.

The raw material gas cylinder required for the annealing treatment of the present invention is replaced, and the gas line is sufficiently purged.
The hydrogen gas and the silicon atom-containing gas necessary for performing the hydrogen plasma treatment of the present invention are introduced into the chamber by valves 461, 4
A predetermined flow rate is introduced into the deposition chamber 418 via 62, the mass flow controllers 456, 457, the valves 451, 452, and the valve 450. The degree of opening and closing of an exhaust valve (not shown) is changed to bring the inside of the deposition chamber 418 to a desired degree of vacuum. In this way, the annealing treatment of the present invention is performed for a predetermined time.

It is desirable to appropriately change the flow rate of hydrogen gas, the flow rate of oxygen atom-containing gas, the substrate temperature, etc. during the annealing treatment depending on the front condition of the substrate and the condition of the inner wall of the chamber. The preferred mode of variation of these parameters is initially to increase the hydrogen flow rate and decrease the hydrogen flow rate over time. As a form of change in the flow rate of the oxygen atom-containing gas, the flow rate of the oxygen atom-containing gas is initially small and the flow rate of the oxygen atom-containing gas increases with time. The substrate temperature is initially high, and it is a preferable form of change that the temperature is lowered over time.

Furthermore, the annealing treatment of the present invention on the i-type layer is performed as follows. Exchange the raw material gas cylinder required for the annealing treatment of the present invention,
Thoroughly purge the gas line. A hydrogen gas and an oxygen atom-containing gas necessary for performing the hydrogen plasma treatment of the present invention are supplied into the chamber through the valves 461 and 462, the mass flow controllers 456 and 457, the valves 451 and 452, and the valve 450 at a predetermined flow rate. To introduce. The degree of opening and closing of an exhaust valve (not shown) is changed to bring the inside of the deposition chamber 418 to a desired degree of vacuum. In this way, the annealing treatment of the present invention is performed for a predetermined time.

It is desirable to appropriately change the flow rate of the hydrogen gas, the flow rate of the oxygen atom-containing gas, the substrate temperature, etc. during the annealing treatment depending on the front condition of the substrate and the condition of the inner wall of the chamber. The preferred mode of variation of these parameters is initially to increase the hydrogen flow rate and decrease the hydrogen flow rate over time. As a form of change in the flow rate of the oxygen atom-containing gas, the flow rate of the oxygen atom-containing gas is initially small and the flow rate of the oxygen atom-containing gas increases with time. A preferable mode of change is that the substrate temperature is initially high and is lowered with time.

The roll-to-roll type forming apparatus shown in FIG. 5 will be described below. Forming device 500
0 indicates the first n-type layer deposition chamber 502 between the load chamber 5010 for introducing the sheet substrate and the unload chamber 5150.
0, first RF-i layer (n / i) deposition chamber 5030, first
MW-i layer deposition chamber 5040, first RF-i layer (p /
i) deposition chamber 5050, first p-type layer deposition chamber 5060, second n-type layer deposition chamber 5070, second RF-i layer (n /
i) deposition chamber 5080, second MW-i layer deposition chamber 509
0, second RF-i layer (p / i) deposition chamber 5100, second
P-type layer deposition chamber 5110 and third n-type layer deposition chamber 512
0, the RF-i layer deposition chamber 5130, and the third p-type layer deposition chamber 5140 are connected together.

A gas gate (5201,
5202, 5203, 5204, 5205, 5206,
5207, 5208, 5209, 5210, 5211,
5212, 5213, 5214). Then, in each gas gate, gas supply pipes (5301, 5302, 5303, 5304, 53) to the gas gate are provided.
05, 5306, 5307, 5308, 5309, 53
10, 5311, 5312, 5313, 5314).

Load chamber 5010 and unload chamber 515
0 and each of the deposition chambers have exhaust pipes (5011, 5021,
5031, 5041, 5051, 5061, 5071,
5081, 5091, 5101, 5111, 5121,
5131, 5141, 5151) through the exhaust pump (5012, 5022, 5032, 5042, 505).
2, 5062, 5072, 5082, 5092, 510
2, 5112, 5122, 5132, 5142, 515
2) is provided.

A source gas supply pipe (502) is provided in each deposition chamber.
5, 5035, 5045, 5055, 5065, 507
5, 5085, 5095, 5105, 5115, 512
5, 5135, 5145) via a mixing device (5
026, 5036, 5046, 5056, 5066, 5
076, 5086, 5096, 5106, 5116, 5
126, 5136, 5146) are provided.

In each deposition chamber, RF supply coaxial cables (5023, 5033, 5043, 5053, 50) are provided.
63, 5073, 5083, 5093, 5103, 51
13, 5123, 5133, 5143) via RF power sources (5024, 5034, 5044, 5054, 506).
4, 5074, 5084, 5094, 5104, 511
4, 5124, 5134, 5144) are provided.

Load chamber 5010 and unload chamber 5150
A sheet feeding jig 5400 and a sheet winding jig 5402 are provided in each of the above. Sheet-shaped substrate 5401 delivered from the sheet delivery jig 5400
Are arranged so as to pass through the deposition chamber 13 and be wound up by the sheet winding jig 5402.

In addition, the MW-i layer deposition chamber (not shown) is connected to a coaxial cable for bias application, a power source, an exhaust gas treatment device, and the like.

Hereinafter, a method of forming a photovoltaic element using the roll-to-roll type forming apparatus shown in FIG. 5 will be described. Numbers in brackets indicate the formation procedure. (1) Ag (or Al-Si) on a stainless steel support
Etc.) and the sheet-like substrate on which the reflection increasing layer such as ZnO is formed are wound into a roll and set in a load chamber 5010 for introducing the sheet-like substrate.

(2) The sheet-shaped substrate is placed in the entire deposition chamber and in the entire gas.
Winding the sheet in the unload chamber 5150 through the gate
Connect to the jig 5402. Exhaust device not shown in each deposition chamber
In 10 ^-3After exhausting to below Torr,
Mixing device 5024, 5034, 5044, 505
4, 5064, 5074, 5084, 5094, 510
Water from 4, 5114, 5124, 5134, 5144
Elementary gas is supplied to each deposition chamber.

(3) Each gas gate 5201, 5202,
5203, 5204, 5205, 5206, 5207,
5208, 5209, 5210, 5211, 5212,
Hydrogen gas is supplied to the gas gates 5213 and 5214 from the gate gas supply devices. The flow rate of the hydrogen gas supplied to the gas gate must be such that the raw material gases in the adjacent deposition chambers do not mix with each other. The preferred flow rate depends on the distance that the gas gate passes through the sheet-shaped substrate. When the distance is 0.5 mm to 5 mm, the hydrogen gas is 200
A preferred flow rate is from sccm to 3000 sccm.

(4) A heater for heating the substrate in each deposition chamber,
The sheet-shaped substrate 5401 is heated to a predetermined substrate temperature. When the substrate temperature stabilizes, the hydrogen gas supplied to each deposition chamber is switched to the desired source gas to be deposited in each deposition chamber.
After switching the source gas, the degree of opening / closing of the exhaust valve of each exhaust device is adjusted to adjust the degree of vacuum in each deposition chamber. (5) The conveyance of the sheet-shaped substrate 5401 is started. After the degree of vacuum is stabilized, RF power or MW power for plasma generation is supplied to each deposition chamber. As described above, a photovoltaic element in which three pin structures are laminated on the sheet substrate is formed.

(6) After forming the photovoltaic element over one roll, the plasma discharge was stopped and the gas gate 5201
Close the pinch valve (valve to hold the vacuum by sandwiching the substrate with plate-shaped rubber) attached to the sheet-like substrate, and leak the load chamber 5010 for sheet-like substrate introduction with nitrogen gas, and roll it up into a sheet-like form. Mount Kisaka 5401. The end of the sheet-shaped substrate 5401 is connected to the end of the sheet-shaped substrate closed by the pinch valve by welding.

(7) The load chamber 5010 is closed and the load chamber is evacuated to a predetermined vacuum level. The pinch valve is opened, plasma discharge is restarted, and formation of the photovoltaic element is started. Similarly, the transportation of the sheet-shaped substrate is started. By repeating the above process, the photovoltaic element is formed on the sheet-shaped substrate wound into a roll.

The deposition film forming chamber 601 by RF plasma CVD in the roll-to-roll type forming apparatus shown in FIG. 6 will be described below. The deposited film forming chamber 601 includes a lamp heater 60 for heating a sheet-shaped substrate.
2. Control plate 60 for adjusting the substrate temperature to a desired temperature distribution
3, a flat plate or grid electrode 604 for introducing RF power substantially parallel to the sheet substrate 616, a heater 605 for preheating a source gas, a source gas introduction pipe 606, an electrode insulating insulator 607, an RF introduction Waveguide 608, exhaust pipe 60
9, raw material gas flow 610, gas gate 611, gas gate gas supply pipe 612, gas gate interval adjusting plate 61
3, adjacent deposition chambers 614 and 615, sheet-like substrate 61
6 and so on.

The source gas for the RF plasma CVD method is heated by the heater 605 for preheating the source gas,
Impurities contained in the raw material gas react with the silane-based raw material gas and deposit on the wall surface. As a result, impurities contained in the source gas are reduced, and a good quality deposited film can be formed.

Further, since the source gas is activated by preheating the source gas, the deposited film can be formed with a relatively low RF power. In particular, this means that when laminating each layer, damage to the lower layer can be kept low,
The interface state between each layer can be reduced. In particular, when a layer is laminated on the MW-i layer of the photovoltaic element of the present invention by the RF plasma CVD method, diffusion of chlorine atoms contained in the MW-i layer is prevented and the photovoltaic element of the photovoltaic element is prevented. It is very effective to preheat the source gas for RF plasma CVD in order to improve the characteristics. A preferable temperature range is 150 to 450 ° C. in gas temperature.

Further, the lamp heater 602 for heating the sheet-shaped substrate is usually arranged so that the substrate temperature becomes uniform in the deposition chamber 601, but in the RF-i layer, the photovoltaic power of the photovoltaic element is increased. It is preferable to arrange the heater so that the substrate temperature becomes lower toward the n-type layer and / or the p-type layer so as to increase.

Furthermore, it is important to arrange cooling pipes on the outer wall of the deposition chamber that covers the discharge space of the RF plasma discharge and circulate the cooling water. By cooling the outer wall of the deposition chamber, it is possible to prevent impurities from being mixed into the deposited film due to degassing from the outer wall of the deposition chamber.
The temperature of the inner wall of the deposition chamber is preferably cooled to 50 ° C. or lower.

Below, the microwave plasma CV in the roll-to-roll type forming apparatus shown in FIG. 7 is used.
The deposition film forming chamber 701 of D will be described.

The deposited film forming chamber 701 includes a substrate heating heater 702, a substrate temperature adjusting control plate 703, a MW introducing window 704, a bias applying bias electrode 705, and a mesh plate for controlling the spread of plasma discharge. 706,
Bias applying cable 708, source gas introduction pipe 70
9, diffusion pump 710, gas gate 711, gas supply pipe 712 to the gas gate, adjacent deposition chambers 713, 71
4, a sheet-shaped substrate 715 and the like, and further connected to a bias applying power source, a mixing panel, a mechanical booster pump, a rotary pump, etc., which are not shown.

In the MW-i layer deposition chamber 701, the heater 702 for heating the substrate is preferably arranged so that the substrate temperature becomes uniform. As an example, see FIG.
It is preferable to arrange the heater in a mountain shape as shown in FIG. Further, it is preferable that a pipe for water cooling is arranged on the outer wall of the deposition chamber to cool the outer wall of the deposition chamber. By cooling the outer wall of the deposition chamber, degassing from the inner wall of the deposition chamber can be suppressed as much as possible, and a high quality deposited film can be formed. The temperature of the inner wall of the deposition chamber is preferably cooled to 50 ° C. or lower in order to reduce degassing.

In the annealing treatment of the present invention in the roll-to-roll system forming apparatus described above, hydrogen gas, helium gas or argon gas containing the oxygen atom-containing gas of the present invention is added to the gas supplied from the gas gate. It is done by pouring.

Further, the gas cylinder used in the method for forming a photovoltaic element for carrying out the annealing treatment of the present invention may be used by appropriately exchanging it with a necessary gas cylinder. In that case, it is preferable that the gas line is sufficiently heated and purged.

A photovoltaic element having a plurality of stacked pin semiconductor layers should be subjected to a desired number of deposition operations in an n-type layer deposition chamber, an i-type layer deposition chamber, and a p-type layer deposition chamber in the forming apparatus 400. Can be formed by.

(Support) As the material of the support in the present invention, there is little deformation and distortion at the temperature required for forming the deposited film, it has desired strength, and it has conductivity. desirable. Further, it is preferable to use a support which does not deteriorate the adhesion of the reflection layer or the reflection increasing layer to the support even when the hydrogen plasma treatment of the present invention is performed after depositing the reflection layer or the reflection increasing layer.

Specifically, for example, thin films of metals such as stainless steel, aluminum and its alloys, iron and its alloys, copper and its alloys, and composites thereof, and metal thin films of different materials and / or their surfaces. SiO ₂ , S
i ₃ N ₄ , Al ₂ O ₃ , AlN or other insulating thin film subjected to surface coating treatment by sputtering, vapor deposition, plating, etc., heat-resistant resin sheet of polyimide, polyamide, polyethylene terephthalate, epoxy, etc. Alternatively, the surface of a composite of these and glass fiber, carbon fiber, boron fiber, metal fiber or the like is subjected to a conductive treatment by a method such as plating, vapor deposition, sputtering or coating with a metal simple substance or an alloy, and a transparent conductive oxide or the like. Something you went to.

The thickness of the support is preferably as thin as possible in consideration of cost, storage space, etc., as long as the curved shape formed when the support is moved is maintained within the range of strength. . Specifically, preferably 0.0
1 mm to 5 mm, more preferably 0.02 mm to 2
The optimum thickness is preferably 0.05 mm to 1 mm, but when a thin film of metal or the like is used, the desired strength can be 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 container and the like. The length of the support is not particularly limited, and may be such a length that it can be wound into a roll or a longer one that is made longer by welding or the like. Absent.

In the present invention, the support is heated / cooled in a short time, but it is not preferable that the temperature distribution spreads in the longitudinal direction of the support. Therefore, it is desirable that the heat conduction in the moving direction of the support is small, and the support is not supported. In order for the body surface temperature to follow heating / cooling, it is preferable that the heat conduction is large in the thickness direction.

In order to reduce the heat conduction of the support in the moving direction and increase the heat conduction in the thickness direction, the thickness may be reduced. When the support is uniform, the value of (heat conduction) × (thickness) is preferably 1 × 10 ⁻¹ W / K or less, more preferably 5 × 10 ^−2.
It is preferably W / K or less.

(Reflective Layer) The material of the reflective layer in the present invention is, for example, Ag, Au, Pt, Ni, Cr, C.
Examples include metals such as u, Al, Ti, Zn, Mo, W, and alloys thereof. Thin films made of these metals are
For example, it is formed by vacuum evaporation, electron beam evaporation, sputtering or the like. In addition, care must be taken so that the formed metal thin film does not become a resistance component to the output of the photovoltaic element, and the sheet resistance value of the reflective layer is preferably 50Ω or less, more preferably 10Ω or less. Is desirable.

When the support is transparent and the photovoltaic element is irradiated with light from the transparent support, a transparent conductive layer is provided instead of the reflective layer. As a transparent conductive layer suitable for such a purpose, for example, tin oxide, indium oxide, or an alloy thereof is suitable. Further, it is preferable that the light-transmissive conductive layer is deposited so as to satisfy the antireflection condition. As the sheet resistance of these translucent conductive layers,
It is preferably 50 Ω or less, more preferably 10 Ω or less.

(Reflection-Increasing Layer) The reflection-increasing layer in the present invention 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. Desirably, the sheet resistance value is 1 so that the output of the photovoltaic element does not electrically become a resistance component.
It is desirable that the value is 00Ω or less. Examples of materials having such characteristics include SnO ₂ , In ₂ O ₃ , and Zn.
O, CdO, Cd ₂ SnO ₄ , ITO (In ₂ O ₃ + SnO
₂ ) and other metal oxides.

The reflection-increasing layer is p-type in the photovoltaic device.
To be laminated on the mold layer or n-type layer half, to form a photovoltaic element on the translucent support, and to irradiate light from the translucent support side, it is laminated on the support. Therefore, it is necessary to select those that have good mutual adhesion.

Further, it is preferable that the reflection increasing layer is deposited in a layer thickness that meets the conditions for increasing the reflection. As a method for producing the reflection increasing layer, for example, a resistance heating vapor deposition method, an electron beam heating vapor deposition method, a sputtering method, a spray method, or the like can be used, and it is appropriately selected as desired.

(I-Type Layer) In the present invention, the i-type layer is pi
The n-junction has a role of generating and transporting carriers for irradiation light. In particular, in a photovoltaic device using an amorphous semiconductor material made of IV group or IV group alloy, the i-type layer is in an important position.

A slightly p-type or n-type layer can be used as the i-type layer. Such a slightly p-type or n-type i-type layer is formed, for example, by adding hydrogen atoms (H, D) to an amorphous semiconductor material.
Alternatively, it is formed by containing a halogen atom (X). As shown below, the inclusions at this time have an important function.

The hydrogen atom (H, D) or halogen atom (X) contained in the i-type layer has a function of compensating for dangling bonds in the i-type layer, and the carrier in the i-type layer is a carrier. It improves the product of the mobility and the life of the. Also,
It has the effect of compensating for the interface states at the interfaces of the p-type layer / i-type layer and the n-type layer / i-type layer, and has the effect of improving the photovoltaic power, photocurrent and photoresponsiveness of the photovoltaic element. It is a thing. In this case, the optimum range of the content of hydrogen atoms and / or halogen atoms contained in the i-type layer is 1 to 40 at%. In particular, a preferable distribution form is one in which the content of hydrogen atoms and / or halogen atoms is largely distributed on each interface side of the p-type layer / i-type layer and the n-type layer / i-type layer. In this case, the content of hydrogen atoms and / or halogen atoms near the interface is preferably in the range of 1.1 to 2 times the content in the bulk. Furthermore, it is preferable that the content of hydrogen atoms and / or halogen atoms be changed corresponding to the content of silicon atoms.

When the photovoltaic element of the present invention has a plurality of pin structures, it is preferable that the i-type layers are laminated in order from the light incident side so that the band gap becomes smaller. Amorphous silicon or amorphous silicon carbide is used for the i-type layer having a relatively wide bandgap, and amorphous silicon germanium is used for the i-type semiconductor layer having a relatively narrow bandgap.

Amorphous silicon and amorphous silicon germanium are formed by elements that compensate for dangling bonds.
a-Si: H, a-Si: F, a-Si: H: F, a-
SiGe: H, a-SiGe: F, a-SiGe: H:
It is written as F or the like. When amorphous silicon germanium is used as the i-type layer, the content of germanium is preferably changed in the layer 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 distribution of germanium atoms in the layer thickness can be controlled by changing the flow rate ratio of the germanium-containing gas contained in the raw material gas.

As a method of changing the content of germanium atoms in the i-type layer by the MW plasma CVD method,
Other than the method of changing the flow rate ratio of the germanium-containing gas, the same can be done by changing the flow rate of hydrogen gas which is a dilution gas of the raw material gas. It is possible to increase the germanium content in the deposited film (i-type layer) by increasing the hydrogen dilution amount.

The hydrogen plasma treatment of the present invention particularly improves the electrical connection between the so-called graded band gap layer in which germanium atoms are continuously changed as described above and the buffer layer in contact with the layer. is there.

More specifically, for example, an i-type hydrogenated amorphous silicon (a-Si: H) is cited as an example of a pin junction i-type semiconductor layer suitable for the photovoltaic element of the present invention. The characteristic is that the optical bandgap (E
_g ) is 1.60 eV to 1.85 eV, hydrogen atom content (C _H ) is 1.0 to 25.0%, AM 1.5, 100 m
The photoelectric conductivity (σ _p ) under simulated sunlight irradiation of W / cm ² is 1.
0 × 10 ⁻⁵ S / cm or more, dark conductivity (σ _d ) 1.0 ×
10 ^-9 S / cm or less, the tilt of the backback tail by the constant photocurrent method (CPM) is 55 m
It is preferably eV or less and the localized level density is 10 ¹⁷ / cm ³ or less.

The amorphous silicon germanium semiconductor material, which constitutes the i-type semiconductor layer having a relatively narrow bandgap of the photovoltaic element of the present invention, has a characteristic that the optical bandgap (E _g ) is 1.20 eV. ~ 1.60 eV,
The hydrogen atom content (C _H ) is 1.0 to 25.0%, the slope of the arback 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 method.

When depositing by the RF plasma CVD method, 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 5.
0 MHz is a suitable range. Especially the RF frequency is 1
3.56 MHz is suitable. The RF power supplied into the deposition chamber is preferably in the range of 0.01 to 5 W / cm ² . The self-bias applied to the substrate by the RF power is preferably 0 to 300V.

When depositing by the VHF plasma CVD method, the substrate temperature is 100 to 450 ° C., the vacuum degree in the deposition chamber is 0.0001 to 1 Torr, and the VHF frequency is 60.
To 99 MHz is a suitable range. The VHF power supplied to the deposition chamber is preferably in the range of 0.01 to 1 W / cm ² . Further, the self-bias applied to the substrate by the VHF power is preferably in the range of 10 to 1000V. Further, the characteristics of the deposited amorphous film are improved by introducing a DC or RF into the deposition chamber by superposing on the VHF or separately providing a bias rod. When introducing a DC bias using a bias rod,
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 the negative electrode. When introducing RF bias, RF is more than substrate area
It is preferable to reduce the area of the electrode into which is introduced.

When depositing by the MW plasma CVD method, the substrate temperature is 100 to 450 ° C., the vacuum degree in the deposition chamber is 0.0001 to 0.05 Torr, and the MW frequency is 100 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 / cm ²
Is a preferable range. MW power is optimally introduced into the deposition chamber via a waveguide. In addition to MW,
By separately providing a bias rod and introducing DC or RF into the deposition chamber, the characteristics of the deposited amorphous film are improved. If the DC bias is introduced using a bias rod, 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 the negative electrode. When introducing the RF bias, it is preferable to make the area of the electrode for introducing the RF smaller than the area of the substrate.

Silane-based source gases such as SiH ₄ , Si ₂ H ₆ , SiF ₄ , and SiF ₂ H ₂ are suitable for depositing the i-type layer suitable for the plasma treatment of the present invention. Further, in order to widen the band gap, it is preferable to add carbon, nitrogen or an oxygen-containing gas. The carbon, nitrogen, or oxygen-containing gas is not contained in the i-type layer uniformly,
It is preferable to add a large amount in the vicinity of the mold layer and / or the n-type layer. By doing so, the open circuit voltage can be improved without alienating the charge running property in the i-type layer. As the carbon-containing gas, C
_n H _{2n + 2} (n is an integer), C _n H _2n (n is an integer), or C ₂ H ₂
Etc. are suitable. As the nitrogen-containing gas, N ₂ , N
O, N ₂ O, NO ₂ , NH _3, etc. are suitable. O ₂ , CO ₂ , O _{3 and the} like are suitable as the oxygen-containing gas. Also, a combination of a plurality of these gases may be introduced. A suitable amount of the source gas for increasing the band gap is 0.1 to 50%.

Further, the characteristics of the i-type layer are improved by adding an element of Group III or / and Group V of the periodic table. Group III elements of the periodic table include B, Al, Ga
Etc. are suitable. Particularly when boron is added, it is preferable to add it by using a gas such as B ₂ H ₆ or BF ₃ . Further, as the group V element of the periodic table, N,
P, As, etc. are suitable. Especially when phosphorus is added, PH ₃ is mentioned as a suitable one. The suitable amount of the group III element and / or the group V element of the periodic table added to the i-type layer is 0.1 to 1000 ppm.

For the i-type layer, 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, in particular i
It is preferable to deposit at a slower 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 preferable that it is smoothly continuous from the i-type layer to the buffer layer.

As a method for continuously changing the bandgap in the buffer layer, the bandgap can be narrowed by increasing the content of germanium atom contained in the silicon-based non-single-crystal semiconductor. Is. On the other hand, the band gap can be continuously widened by increasing the content of carbon atoms, oxygen atoms and / or nitrogen atoms contained in the silicon-based non-single crystal semiconductor. It is a preferable range that the ratio between the narrowest part and the widest part of the band gap is 1.01 to 1.5.

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

(P-Type Layer, n-Type Layer) The p-type layer or the n-type layer in the present invention is an important layer that influences the characteristics of the photovoltaic device of the present invention, like the above-mentioned i-type layer. .

As an amorphous material (denoted as a-) (microcrystalline material (denoted as μc-)) of the p-type layer or n-type layer, it goes without saying that it falls into the category of amorphous materials. Is, for example, a-Si: H, a-Si: HX, a-Si
C: H, a-SiC: HX, a-SiGe: H, a-S
iGeC: H, a-SiO: H, a-SiN: H, a-
SiON: HX, a-SiOCN: HX, μc-Si:
H, μc-SiC: H, μc-Si: HX, μc-Si
C: HX, μc-SiGe: H, μc-SiO: H, μ
c-SiGeC: H, μc-SiN: H, μc-SiO
N: HX, μc-SiOCN: HX, etc. and a p-type valence electron control agent (Group III atom B, Al, Ga, I of the periodic table)
(n, Tl) or an n-type valence electron control agent (group V atom P, As, Sb, Bi of the periodic table) is added at a high concentration.

Polycrystalline material of the p-type layer or n-type layer (poly)
Is displayed), for example, poly-Si:
H, poly-Si: HX, poly-SiC: H, p
poly-SiC: HX, poly-SiGe: H, po
poly-SiC, poly-SiC, poly-SiGe,
And a p-type valence electron control agent (group III atom B of the periodic table,
Examples thereof include Al, Ga, In, Tl) and n-type valence electron control agents (group V atoms P, As, Sb, Bi in the periodic table) added in high concentration.

Particularly, in the p-type layer or the n-type layer on the light incident side,
A crystalline semiconductor layer with little light absorption or an amorphous semiconductor layer with a wide band gap is suitable.

The amount of Group III atoms added to the p-type layer and the amount of Group V atoms added to the n-type layer are
The optimum amount is 0.1 to 50 at%.

Further, the hydrogen atom (H, D) or halogen atom contained in the p-type layer or the n-type layer has a function of compensating for dangling bonds of the p-type layer or the n-type layer. It improves the doping efficiency of the n-type layer. p-type layer or n
The number of hydrogen atoms or halogen atoms added to the mold layer is 0.1.
-40 at% is mentioned as the optimum amount. Especially 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%.

Further, a preferable distribution form is one in which the content of hydrogen atoms and / or halogen atoms is distributed in a large amount on each interface side of the p-type layer / i-type layer and the n-type layer / i-type layer. . At this time, the content of hydrogen atoms and / or halogen atoms near the interface is preferably in the range of 1.1 to 2 times the content in the bulk.
Thus, by increasing the content of hydrogen atoms or halogen atoms in the vicinity of each interface of 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. It is possible to increase the photovoltaic power and the photocurrent of the photovoltaic device of the present invention.

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

In the microwave plasma CVD method, a material gas such as a source gas and a diluent gas is introduced into the deposition chamber,
While evacuating with a vacuum pump, the internal pressure of the deposition chamber was kept constant, and microwaves oscillated by a microwave power source were guided by a waveguide and introduced into the deposition chamber through a dielectric window (alumina ceramics etc.). Is a method of generating plasma of material gas and decomposing it to form a desired deposited film on the substrate placed in the deposition chamber. The deposited film applicable to the photovoltaic device is formed under wide deposition conditions. can do.

As the 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 gasifiable compound containing a silicon atom, germanium atom, is used. A gasifiable compound containing,
Examples thereof include a gasizable compound containing a carbon atom, a gasizable compound containing a nitrogen atom, a gasizable compound containing an oxygen atom, and a mixed gas of the compound.

A chain-like or cyclic silane compound is used as the gasifiable compound containing silicon atoms. Specifically, for example, SiH ₄ , Si ₂ H ₆ and Si are used.
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.

A gas containing specifically germanium atoms
GeH is a compound that can be converted into_Four, GeD_Four, GeF_Four,
GeFH_Three, GeF₂H₂, GeF_ThreeH, GeHD_Three, Ge
H₂D ₂, GeH_ThreeD, GeH₆, Ge₂D₆Etc.
You.

Specific examples of the gasifiable compound containing a carbon atom include CH ₄ , CD ₄ , C _n H _{2n + 2} (n is an integer), C _n H _2n (n is an integer), C ₂ H ₂ , C ₆ H ₆ , CO ₂ ,
CO etc. are mentioned.

As the nitrogen-containing gas, N ₂ , NH ₃ , N
D _3, NO, include NO _2, N ₂ O. Oxygen-containing gas includes O ₂ , CO, CO ₂ , NO, NO ₂ , N ₂ O, CH
₃ CH ₂ OH, CH ₃ OH and the like can be mentioned.

Further, as the substance introduced into the p-type layer or the n-type layer for controlling the valence electrons, there are group III atoms and group V atoms of the periodic table.

The materials effectively used as a starting material for introducing a Group III atom include B ₂ H ₆ , B ₄ H ₁₀ , B ₅ H ₉ , and B ₅ specifically for introducing a boron atom. H ₁₁ , B
_{6 H 1 0, B 6 H} 12, B 6 H 14 , etc. borohydride, BF _3, B
Examples thereof include boron halides such as Cl ₃ .
In addition, AlCl ₃ , GaCl ₃ , InCl ₃ , TlC
Examples include l _{3 and the} like. B ₂ H ₆ and BF ₃ are particularly suitable.

Effectively used as a starting material for introducing a Group V atom is specifically P for introducing a phosphorus atom.
Phosphorus hydride such as H ₃ and P ₂ H ₄ , PH ₄ I, PF ₃ , and PF ₅ ,
Examples thereof include phosphorus halides such as PCl ₃ , PCl ₅ , PBr ₃ , PBr ₅ , and PI ₃ . In addition, AsH ₃ , AsF ₃ ,
_{AsCl 3, AsBr 3, AsF 5} , SbH 3, SbF 3,
SbF ₅ , SbCl ₃ , SbCl ₅ , BiH ₃ , BiC
Other examples include l ₃ and BiBr ₃ . Especially PH ₃ ,
PF ₃ is suitable.

In addition, the gasifiable compound is replaced by H ₂ , H
It may be appropriately diluted with a gas such as e, Ne, Ar, Xe, or Kr and introduced into the deposition chamber.

In particular, when depositing a layer having a small band of light absorption or a wide band gap, such as a microcrystalline semiconductor or a-SiC: H, the source gas is diluted 2 to 100 times with hydrogen gas, and microwave power or RF is applied. It is preferable to introduce a relatively high power.

(Transparent Electrode) The transparent electrode in the present invention is
In order to efficiently absorb the light from the sun, white fluorescent lamps, etc. in each semiconductor layer, it is desirable that the light transmittance is 85% or more. Furthermore, electrically, the resistance of the output of the photovoltaic element is high. Sheet resistance is 100 so that it does not become a component
Ω or less is desirable. Examples of materials having such special characteristics include SnO ₂ , In ₂ O ₃ , ZnO, CdO, and C.
Examples thereof include metal oxides such as d ₂ SnO ₄ and ITO (In ₂ O ₃ + SnO ₂ ), and metal thin films formed by forming a metal such as Au, Al and Cu in an extremely thin and semitransparent state. (Transparent Electrode) In the photovoltaic element, the transparent electrode is laminated on the p-type layer or the n-type layer half to form the photovoltaic element on the translucent support, and light is transmitted from the translucent support side. In the case of irradiation, it is to be laminated on the support, so it is necessary to select those having good mutual adhesion. Further, it is preferable that the transparent electrode is deposited in a layer thickness suitable for the antireflection condition. As a method for manufacturing the transparent electrode, 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.

(Collector Electrode) As the collector electrode of the photovoltaic element which has been subjected to the hydrogen plasma treatment in the present invention, for example, a silver paste formed by a screen printing method, Cr,
A material in which Ag, Au, Cu, Ni, Mo, Al, or the like is formed by a vacuum vapor deposition method using a mask is preferably used. Alternatively, a metal wire of Cu, Au, Ag, Al or the like may be attached with carbon or Ag powder together with a resin and attached to the surface of the photovoltaic element to form a collector electrode.

When a photovoltaic device having a desired output voltage and output current is manufactured using the photovoltaic element of the present invention, the photovoltaic elements of the present invention are connected in series or in parallel, A protective layer is formed on the front and back surfaces, and output extraction 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.

[0143]

EXAMPLES The photovoltaic element of the present invention will be described in detail below by making a solar cell made of a non-single crystal silicon semiconductor material, but the present invention is not limited thereto.

(Example 1) In this example, the photovoltaic element shown in FIG. 1 was produced using the in-line forming apparatus shown in FIG. The manufacturing method will be described below according to the procedure. (1) A substrate was manufactured. Thickness 0.5mm, 50x5
A 0 mm ² stainless support (100) was ultrasonically washed with acetone and isopropanol and dried with warm air.
A light-reflecting layer (101) of Ag having a layer thickness of 0.3 μm and a Zn layer having a layer thickness of 1.0 μm at 350 ° C. were formed on the surface of a stainless support (100) at room temperature using a sputtering method.
An O reflection increasing layer (102) was formed, and the fabrication of the substrate was completed.

(2) The deposition apparatus 400 can carry out both the MWPCVD method and the RFPCVD method. Using this, each semiconductor layer was formed on the reflection increasing layer. A source gas cylinder (not shown) is connected to the deposition apparatus through a gas introduction pipe. The raw material gas cylinders are all refined to ultra-high purity. As a raw material gas cylinder,
SiH ₄ gas cylinder, O ₂ / H ₂ (dilution level: 1 ppm) gas cylinder, O ₂ / He (dilution level: 10 ppm) gas cylinder, O ₂ / Ar (dilution level 100 ppm) gas cylinder, O ₂
/ H ₂ (dilution: 1000 ppm) gas cylinder, CH ₄ gas cylinder, GeH ₄ gas cylinder, Si ₂ H ₆ gas cylinder,
PH ₃ / H ₂ (dilution: 0.1%) gas cylinder, B ₂ H ₆ /
H ₂ (dilution: 0.2%) gas cylinder, H ₂ gas cylinder,
He gas cylinder, SiCl ₂ H ₂ gas cylinder, SiH ₄ /
A H ₂ (dilution: 1%) gas cylinder was connected.

(3) The substrate on which the reflection layer 101 and the reflection increasing layer 102 are formed is placed on the substrate transfer rail 413 in the load chamber 401, and the load chamber 401 is pressurized by a vacuum exhaust pump (not shown). About 1 x 10
^It was evacuated to ^-5 Torr. Next, the gate valve 406 was opened and the film was transferred into the transfer chamber 402 and the deposition chamber 417 which were evacuated by a vacuum exhaust pump (not shown) in advance. The back surface of the substrate is brought into close contact with the substrate heating heater 410 to heat the substrate, and the deposition chamber 41
7 has a pressure of about 1 × 10 by a vacuum pump (not shown).
^It was evacuated to ^-5 Torr.

(4) After the preparation for film formation is completed as described above, H ₂ gas is introduced into the deposition chamber 417 through the gas introduction pipe 429, and the H ₂ gas flow rate is 500 sccc.
Open the valves 441, 431, 430 so that
It was adjusted with the mass flow controller 436. The pressure in the deposition chamber 417 was adjusted to 1.0 Torr by a conductance valve (not shown). The substrate heating heater 410 was set so that the substrate temperature was 350 ° C.

(5) When the substrate temperature is stable, μc
The RF n-type layer 103 made of —Si was formed. μc-S
To form an RF n-type layer made of i, SiH ₄ gas,
PH ₃ / H ₂ gas is introduced into the deposition chamber 417 by the valve 44.
Operate 3, 433, 444, 434 to operate the gas introduction pipe 42
Introduced through 9. At this time, the SiH ₄ gas flow rate is 2 s
The mass flow controllers 438, 436, and 439 were adjusted so that the ccm and H ₂ gas flow rates were 100 sccm and the PH ₃ / H ₂ gas flow rate was 200 sccm, and the pressure inside the deposition chamber 417 was adjusted to 1.0 Torr.

The power of the RF power source 422 is 0.05 W / cm.
Set to ² , RF power is introduced into the plasma forming cup 420, glow discharge is generated, formation of the RFn type layer is started on the substrate, and the RF power source is turned off when the RFn type layer having a layer thickness of 20 nm is formed. Then, the glow discharge was stopped and the formation of the RF n-type layer 103 was completed. Stop the inflow of SiH ₄ gas, PH ₃ / H ₂ gas, and H ₂ gas into the deposition chamber 417,
The deposition chamber and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

(6) Next, an annealing treatment was performed in a gas atmosphere containing a trace amount of oxygen atoms according to the present invention. In order to perform the annealing treatment in the atmosphere of the gas containing a small amount of oxygen atoms of the present invention, as the oxygen atom containing gas, O ₂ / H ₂ (dilution: 1 p
pm) gas into the deposition chamber 417
9 and introduced into the valve 442, 43 so that the O ₂ / H ₂ (dilution degree: 1 ppm) gas flow rate was 500 sccm.
2 was opened and adjusted with the mass flow controller 437. The pressure in the deposition chamber 417 was adjusted to 1.0 Torr by a conductance valve (not shown).

The heater 410 for heating the substrate was set so that the temperature of the substrate was 350 ° C., and the annealing treatment in the gas atmosphere containing a small amount of oxygen atoms of the present invention was performed for 10 minutes.
Next, O ₂ / H ₂ (dilution: 1
(ppm) gas was stopped, and the inside of the deposition chamber 417 and the gas pipe was evacuated to 1 × 10 ⁻⁵ Torr.

(7) Next, the RFi type layer 151 made of a-Si, the MWi type layer 104 made of a-SiGe, and a-
RFi type layer 161 made of Si, R made of a-SiC
The Fp type layer 105 was sequentially formed.

(7-1) First, the transfer chamber 4 previously evacuated by a vacuum exhaust pump (not shown).
03 and the i-type layer deposition chamber 418, the gate valve 407 was opened and the substrate was transported. The back surface of the substrate was brought into close contact with the heater 411 for heating the substrate and heated, and the inside of the i-type layer deposition chamber 418 was evacuated to a pressure of about 1 × 10 ⁻⁵ Torr by a vacuum exhaust pump (not shown).

To prepare the RFi type layer, the substrate heating heater 411 is set so that the substrate temperature is 300 ° C., and when the substrate is sufficiently heated, the valves 464 and 45 are formed.
4, 450, 463, 453 are gradually opened and Si ₂ H ₆
Gas and H ₂ gas were caused to flow into the i-type layer deposition chamber 418 through the gas introduction pipe 449. At this time, the mass flow controllers 459 and 4 were adjusted so that the Si ₂ H ₆ gas flow rate was 4 sccm and the H ₂ gas flow rate was 110 sccm.
Adjusted at 58. 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 0.008 W / c.
Setting to m ² , applying to the bias rod 428, causing glow discharge, opening the shutter 427 to start the production of the i-type layer on the RF n-type layer, and when the i-type layer having a layer thickness of 10 nm was produced. Stop RF glow discharge, RF power supply 42
The output of No. 4 was cut off, and the fabrication of the RFi type layer 151 was completed. The valves 464, 454, 453, and 450 are closed to stop the inflow of Si ₂ H ₆ gas and H ₂ gas into the i-type layer deposition chamber 418 and 1 × 10 ⁻ in the i-type layer deposition chamber 418 and the gas pipe. ^It was evacuated to ⁵ Torr.

(7-2) To prepare the MWi type layer, the heater 4 for heating the substrate is set so that the temperature of the substrate becomes 380 ° C.
11 is set and the valve 4 is heated when the substrate is sufficiently heated.
61, 451, 450, 462, 452, 463, 45
3 is gradually opened, and SiH ₄ gas, GeH ₄ gas, and H ₂ gas are introduced into the i-type layer deposition chamber 4 through the gas introduction pipe 449.
It was made to flow into 18.

At this time, the SiH ₄ gas flow rate is 50 scc
m, GeH ₄ gas flow rate is 35 sccm, H ₂ gas flow rate is 1
The mass flow controllers 456, 457, and 458 were adjusted so as to be 50 sccm. The pressure inside the i-type layer deposition chamber 418 was adjusted to 6 mTorr by adjusting the opening of a conductance valve (not shown). Next, the RF power source 424 was set to 0.30 W / cm ² and applied to the bias rod 428. After that, the power of a μW power source (2.45 GHz) not shown is set to 0.10 W / cm ² , and μW power is introduced into the i-type layer deposition chamber 418 through the waveguide 426 and the microwave introduction window 425. ,
Glow discharge is caused to occur, and the shutter 427 is opened to start the preparation of the MWi type layer on the RFi type layer, and the layer thickness of 0.
When the 17 μm i-type layer was formed, μW glow discharge was stopped, the output of the bias power supply 424 was turned off, and the MWi-type layer 1
Production of 04 was completed. The valves 451, 452, 453 are closed to stop the inflow of SiH ₄ gas, GeH ₄ gas, and H ₂ gas into the i-type layer deposition chamber 418, and the inside of the i-type layer deposition chamber 418 and the gas pipe are set to 1 × 10. ^-5 Tor
It was evacuated to r.

(7-3) To prepare the RFi type layer, the heater 4 for heating the substrate is set so that the temperature of the substrate becomes 250 ° C.
11 is set and the valve 4 is heated when the substrate is sufficiently heated.
64, 454, 450, 463, 453 were gradually opened, and Si ₂ H ₆ gas and H ₂ gas were caused to flow into the i-type layer deposition chamber 418 through the gas introduction pipe 449. At this time, the Si ₂ H ₆ gas flow rate is 3 sccm and the H ₂ gas flow rate is 8 sc
The mass flow controllers 459 and 458 were adjusted so as to be 0 sccm. i-type layer deposition chamber 4
The opening of a conductance valve (not shown) was adjusted so that the pressure inside 18 was 0.7 Torr.

Next, the RF power source 424 is set to 0.007 W / c.
After setting to m ² , applying a bias rod 428 to cause glow discharge and opening the shutter 427, the preparation of the RFi-type layer on the MWi-type layer was started, and the i-type layer with a layer thickness of 20 nm was prepared. The RF glow discharge was stopped, the output of the RF power source 424 was cut off, and the fabrication of the RFi type layer 161 was completed. Close valves 464, 454, 453, 450,
The inflow of Si ₂ H ₆ gas H ₂ gas into the i-type layer deposition chamber 418 was stopped, and the i-type layer deposition chamber 418 and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

(8) Next, in order to form the RFp type layer 105 made of a-SiC, the transfer chamber 404 which has been evacuated by a vacuum exhaust pump (not shown) in advance.
And gate valve 40 into the p-type layer deposition chamber 419.
8 was opened and the substrate was transported. The back surface of Kisaka 490 was brought into close contact with the substrate heating heater 412 and heated, and the inside of the p-type layer deposition chamber 419 was evacuated to a pressure of about 1 × 10 ⁻⁵ Torr by a vacuum exhaust pump (not shown).

The substrate is heated so that the temperature of the substrate becomes 230.degree.
Set the heater for heat 412 and make sure that the substrate temperature is stable.
By the way, H₂Gas, SiH_Four/ H₂Gas, B₂H₆/ H₂gas,
CH _FourA gas is introduced into the deposition chamber 419 through a valve 481;
471, 470, 482, 472, 483, 473, 4
Operate 84, 474 and introduce through gas introduction pipe 469
did. At this time, H₂Gas flow rate is 60 sccm, SiH_Four/
H₂Gas flow rate is 2 sccm, B₂H₆/ H₂Gas flow rate is 10
sccm, CH_FourGas flow rate should be 0.3 sccm
Mass flow controllers 476, 477, 478,
The pressure in the deposition chamber 419 is adjusted to 2.
Conductance valve not shown so as to be 0 Torr
Adjusted the opening.

The power of the RF power source 423 is 0.07 W / cm.
² is set, RF power is introduced into the plasma forming cup 421 to cause glow discharge, start forming an RF p-type layer on the i-type layer, and form an RF p-type layer having a layer thickness of 10 nm. Turn off, stop glow discharge, RFp
The formation of the mold layer 205 is completed. Valves 472, 482, 4
73, 483, 474, 484, 471, 481, 47
0 to close SiH ₄ into the p-type layer deposition chamber 419.
/ H ₂ gas, B ₂ H ₆ / H ₂ gas, CH ₄ gas, and H ₂ gas were stopped, and the inside of the p-type layer deposition chamber 419 and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Next, the gate valve 409 is opened into the unload chamber 405 which has been evacuated by a vacuum exhaust pump (not shown) in advance, the substrate is transferred, and a leak valve (not shown) is opened to leak the unload chamber 405. did.

(9) Next, ITO having a layer thickness of 70 nm was vacuum-deposited on the RF p-type layer 105 as a transparent conductive layer 112 by a vacuum vapor deposition method. (10) Next, a mask having comb-shaped holes is placed on the transparent conductive layer 112, and Cr (40 nm) / Ag (1000 n
m) / Cr (40 nm) comb-shaped collector electrode 113
Was vacuum deposited by a vacuum deposition method.

The fabrication of the photovoltaic element of this example was completed above. This photovoltaic element is called (SC Ex 1). Further, an annealing treatment in a gas atmosphere containing a trace amount of oxygen atoms according to the present example, an RFn type layer, an RFi type layer, an MWi type layer,
The conditions for forming the RF p-type layer are shown in Tables 12 and 13.

Comparative Example 1-1 This example is different from Example 1 in that the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms was not performed.

Other points were the same as in Example 1. The photovoltaic element of this example is called (SC ratio 1-1).

Eight of each of the above-mentioned two types of photovoltaic elements (SC Ex 1) and (SC ratio 1-1) were produced.
Table 1 shows the characteristics of the initial photoelectric conversion efficiency (photovoltaic power / incident light power) and the characteristic unevenness for each of these photovoltaic devices.
Photodegradation characteristics, environment resistance characteristics in high temperature and high humidity environment, cross section S
It is an evaluation result of EM observation and adhesion measurement.

Table 1 shows the results of the photovoltaic element (SC ratio 1-1), and the normalized results of the photovoltaic element (SC Ex 1) are shown.

[0170]

[Table 1] However, the characteristics of the initial photoelectric conversion efficiency were obtained by placing the manufactured photovoltaic element under AM-1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristics. The characteristic unevenness of the initial photoelectric conversion efficiency is a variation in the initial photoelectric conversion efficiency in each of the eight photovoltaic elements.

The photodegradation characteristic means that the temperature of the photovoltaic element is 5
1000 at 1 m under 100 mW / cm ² at 0 ° C
It is the rate of decrease in the photoelectric conversion efficiency evaluated after irradiation for a period of time.

The environmental resistance is defined as the photoelectric conversion evaluated under an atmospheric temperature of 80 ° C., a humidity of 80%, a dark place for 100 hours, a photovoltaic element temperature of 25 ° C., and a sun of 100 mW / cm ^2. This is the rate of decrease in efficiency.

The cross-section SEM observation is the result of evaluating the cross-section of the photovoltaic element using a SEM (model number: S-4500, magnification: 50,000 times) manufactured by Hitachi, Ltd. to evaluate the occurrence of microcracks. As the microcracks, those having a size of 10 nm or more were measured, and the number of occurrence per unit area was measured.

The adhesion measurement is a result of observing the state of layer delamination with an optical microscope (bright field, 1000 times) manufactured by Olympus Corporation with respect to the sample used for SEM observation of the cross section.

From the results shown in Table 1, the photovoltaic element of Example 1 (SC Ex 1) is superior to the photovoltaic element of Comparative Example 1-1 (SC ratio 1-1) in all evaluation results. I found out.

Example 2 In this example, the tandem photovoltaic element shown in FIG. 2 was produced using the in-line forming apparatus shown in FIG. The manufacturing method will be described below according to the procedure. (1) Reflective layer 2 prepared by the same method as in Example 1
01 and the substrate on which the reflection increasing layer 202 is formed are placed on the substrate transfer rail 413 in the load chamber 401, and the load chamber 4 is loaded by a vacuum exhaust pump (not shown).
The inside of the chamber No. 01 was evacuated until the pressure reached about 1 × 10 ⁻⁵ Torr.

(2) Next, the transfer chamber 402 previously evacuated by a vacuum exhaust pump (not shown)
Then, the gate valve 406 was opened and conveyed into the deposition chamber 417. The back surface of the substrate is a heater 410 for heating the substrate.
Then, the deposition chamber 417 was evacuated to a pressure of about 1 × 10 ⁻⁵ Torr by a vacuum exhaust pump (not shown).

(3) After the preparation for film formation is completed as described above, H ₂ gas is introduced into the deposition chamber 417 through the gas introduction pipe 429, and the H ₂ gas flow rate is 500 sccc.
Open the valves 441, 431, 430 so that
It was adjusted with the mass flow controller 436. The pressure in the deposition chamber 417 was adjusted to 1.0 Torr by a conductance valve (not shown). The substrate heating heater 410 was set so that the substrate temperature was 350 ° C.

(4) When the substrate temperature is stable, μc
An RFn type layer 203 made of —Si was formed. μc-S
To form an RF n-type layer made of i, SiH ₄ gas,
PH ₃ / H ₂ gas is introduced into the deposition chamber 417 by the valve 44.
Operate 3, 433, 444, 434 to operate the gas introduction pipe 42
Introduced through 9. At this time, the SiH ₄ gas flow rate is 2 s
The mass flow controllers 438, 436, and 439 were adjusted so that the ccm and H ₂ gas flow rates were 100 sccm and the PH ₃ / H ₂ gas flow rate was 200 sccm, and the pressure inside the deposition chamber 417 was adjusted to 1.0 Torr.

The power of the RF power source 422 is 0.05 W / cm.
Set to ² , RF power is introduced into the plasma forming cup 420, glow discharge is generated, formation of the RFn type layer is started on the substrate, and the RF power source is turned off when the RFn type layer having a layer thickness of 20 nm is formed. Then, the glow discharge was stopped and the formation of the RFn-type layer 203 was completed. Stop the inflow of SiH ₄ gas, PH ₃ / H ₂ gas, and H ₂ gas into the deposition chamber 417,
The deposition chamber and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

(5) Next, an annealing treatment was performed in a gas atmosphere containing a trace amount of oxygen atoms according to the present invention. In order to perform the annealing treatment in the atmosphere of the gas containing a small amount of oxygen atoms of the present invention, O ₂ / He (dilution: 1
0 ppm) gas was introduced into the deposition chamber 417 through the gas introduction pipe 429, and O ₂ / He (dilution degree: 10 pp
m) Valve 44 so that the gas flow rate is 500 sccm
2, 432 were opened and adjusted with the mass flow controller 437. The pressure in the deposition chamber 417 is 1.0 To
The conductance valve (not shown) was used to adjust to rr. The heater 410 for heating the substrate was set so that the temperature of the substrate was 350 ° C., and the annealing treatment was performed for 10 minutes in the atmosphere of the gas containing a small amount of oxygen atoms of the present invention. Next, O ₂ / He into the deposition chamber 417 (dilution: 10 p
pm) gas was stopped, and the inside of the deposition chamber 417 and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

(6) Next, the RFi type layer 251 made of a-Si, the MWi type layer 204 made of a-SiGe, and a-
RFi type layer 261 made of Si, R made of a-SiC
Fp type layer 205, RFn type layer 20 made of μc-Si
6. An RFi type layer 207 made of a-Si and an RFp type layer 208 made of a-SiC were sequentially formed.

(6-1) First, the transfer chamber 4 previously evacuated by a vacuum exhaust pump (not shown).
03 and the i-type layer deposition chamber 418, the gate valve 407 was opened and the substrate was transported. The back surface of the substrate was brought into close contact with the heater 411 for heating the substrate and heated, and the inside of the i-type layer deposition chamber 418 was evacuated to a pressure of about 1 × 10 ⁻⁵ Torr by a vacuum exhaust pump (not shown).

(6-2) To manufacture the RFi type layer 251, the substrate heating heater 411 is set so that the temperature of the substrate becomes 300 ° C., and when the substrate is sufficiently heated, the valves 464, 454, 450. , 463, 453 were 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 458 were adjusted so that the Si ₂ H ₆ gas flow rate was 4 sccm and the H ₂ gas flow rate was 110 sccm. The opening of the conductance valve (not shown) was adjusted so that the pressure inside the i-type layer deposition chamber 418 was 0.7 Torr.

Next, the RF power source 424 is set to 0.008 W / c.
Setting to m ² , applying to the bias rod 428, causing glow discharge, opening the shutter 427 to start the production of the i-type layer on the RF n-type layer, and when the i-type layer having a layer thickness of 10 nm was produced. Stop RF glow discharge, RF power supply 42
The output of No. 4 was cut off, and the fabrication of the RFi type layer 151 was completed. The valves 464, 454, 453, and 450 are closed to stop the inflow of Si ₂ H ₆ gas and H ₂ gas into the i-type layer deposition chamber 418 and 1 × 10 ⁻ in the i-type layer deposition chamber 418 and the gas pipe. ^It was evacuated to ⁵ Torr.

(6-3) To prepare the MWi-type layer 204, the substrate heating heater 411 is set so that the temperature of the substrate becomes 380 ° C., and when the substrate is sufficiently heated, the valves 461, 451 and 450. , 462, 452, 46
3, 453 were gradually opened, and SiH ₄ gas, GeH ₄ gas, and H ₂ gas were caused to flow into the i-type layer deposition chamber 418 through the gas introduction pipe 449. At this time, the SiH ₄ gas flow rate is 50 sccm and the GeH ₄ gas flow rate is 55 sccc.
The mass flow controllers 456, 457, and 458 were adjusted so that the m and H ₂ gas flow rates were 150 sccm. The pressure inside the i-type layer deposition chamber 418 is 6 m.
The conductance valve opening (not shown) was adjusted so as to be Torr.

Next, the RF power source 424 is set to 0.30 W / cm.
^It was set to ² and applied to the bias rod 428. After that, the power of the μW power supply (2.45 GHz) not shown is set to 0.10 W.
Set / cm ^2, .mu.W the i-type layer deposition chamber 418 through the waveguide 426 and microwave introducing window 425,
Shutter 427 is activated by introducing electric power and causing glow discharge.
Opening the opening to start the formation of the MWi-type layer on the RFi-type layer, and when the i-type layer having a layer thickness of 0.15 μm was formed, μW
Stop glow discharge, turn off output of bias power supply 424,
The fabrication of the MWi type layer 204 is completed. Valves 451 and 45
2, 453 are closed to stop the inflow of SiH ₄ gas, GeH ₄ gas and H ₂ gas into the i-type layer deposition chamber 418,
1 × in the i-type layer deposition chamber 418 and the gas pipe
It was evacuated to 10 ^-5 Torr.

(6-4) To manufacture the RFi-type layer 261, the substrate heating heater 411 is set so that the temperature of the substrate becomes 250 ° C., and when the substrate is sufficiently heated, the valves 464, 454, 450. , 463, 453 were 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 458 were adjusted so that the Si ₂ H ₆ gas flow rate was 3 sccm and the H ₂ gas flow rate was 80 sccm. The opening of the conductance valve (not shown) was adjusted so that the pressure in the i-type layer deposition chamber 418 became 0.7 Torr.

Next, the RF power source 424 is set to 0.007 W / c.
After setting to m ² , applying a bias rod 428 to cause glow discharge and opening the shutter 427, the preparation of the RFi-type layer on the MWi-type layer was started, and the i-type layer with a layer thickness of 20 nm was prepared. The RF glow discharge was stopped, the output of the RF power supply 424 was cut off, and the fabrication of the RFi type layer 261 was completed. Close valves 464, 454, 453, 450,
Si ₂ H ₆ gas, H _{2 in the} i-type layer deposition chamber 418
The inflow of gas was stopped, 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.

(6-5) Next, RF composed of a-SiC
In order to form the p-type layer 205, the transfer chamber 4 previously evacuated by a vacuum exhaust pump (not shown).
04 and the p-type layer deposition chamber 419, the gate valve 408 was opened and the board | substrate was conveyed. The back surface of the substrate was brought into close contact with the substrate heating heater 412 and heated, 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 substrate is heated so that the temperature of the substrate becomes 230 ° C.
Set the heater for heat 412 and make sure that the substrate temperature is stable.
By the way, H₂Gas, SiH_Four/ H₂Gas, B₂H₆/ H₂gas,
CH _FourA gas is introduced into the deposition chamber 419 through a valve 481;
471, 470, 482, 472, 483, 473, 4
Operate 84, 474 and introduce through gas introduction pipe 469
did. At this time, H₂Gas flow rate is 60scm, SiH_Four/ H
₂Gas flow rate is 2 sccm, B₂H₆/ H₂Gas flow rate is 10s
ccm, CH_FourSo that the gas flow rate is 0.3 sccm
Mass flow controller 476, 477, 478, 4
The pressure inside the deposition chamber 419 is adjusted to 2.0 by adjusting 79.
The conductance valve (not shown) is set to Torr.
The opening was adjusted.

The power of the RF power source 423 is 0.07 W / cm ²
And RF power was introduced into the plasma forming cup 421 to cause glow discharge, the formation of the RF p-type layer on the i-type layer was started, and the RF power source was turned on when the RF p-type layer having a layer thickness of 10 nm was formed. After that, the glow discharge was stopped, and the formation of the RF p-type layer 205 was completed. Valves 472, 482, 47
3, 483, 474, 484, 471, 481, 470
Closed and the SiH ₄ / inside the p-type layer deposition chamber 419
The inflow of H ₂ gas, B ₂ H ₆ / H ₂ gas, CH ₄ gas, and H ₂ gas was stopped, and the inside of the p-type layer deposition chamber 419 and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

(6-6) Next, RF consisting of μc-Si
In order to form the n-type layer 206, the gate valves 408 and 407 were opened and transferred into the transfer chamber 402 and the deposition chamber 417 through the transfer chamber 403 which was evacuated in advance by a vacuum exhaust pump (not shown). The back surface of the substrate was brought into close contact with the substrate heating heater 410 to heat it, 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.

To form the RFn-type layer made of μc-Si, H ₂ gas was introduced into the deposition chamber 417 through the gas introduction pipe 429, and the H ₂ gas flow rate was 200 sccm.
The valves 441, 431, and 430 were opened so as to be set, and the mass flow controller 436 adjusted. The pressure in the deposition chamber 417 was adjusted to 1.0 Torr by a conductance valve (not shown).

The substrate heating heater 410 was set so that the substrate temperature was 225 ° C. When the substrate temperature became stable, SiH ₄ gas and PH ₃ / H ₂ gas were introduced into the deposition chamber 417 by valves 443, 433, 444 and 434 were operated and introduced through the gas introduction pipe 429. At this time, S
iH ₄ gas flow rate is ₂ sccm, H ₂ gas flow rate is 50 sccc
m, PH ₃ / H ₂ gas flow rate was adjusted to 250 sccm by mass flow controllers 438, 436, 439, and the pressure in the deposition chamber 417 was 1.0 Torr.
Was adjusted so that

The power of the RF power source 422 is 0.04 W / cm.
² is set, RF power is introduced into the plasma forming cup 420 to cause glow discharge, and RFn is formed on the RF p-type layer.
The formation of the mold layer is started, and when the RFn type layer having a layer thickness of 10 nm is formed, the RF power supply is turned off to stop the glow discharge, and R
The formation of the Fn type layer 206 is completed. Deposition chamber 417
The flow of SiH ₄ gas, PH ₃ / H ₂ gas, and H ₂ gas into the chamber was stopped, and the inside of the deposition chamber and the gas pipe was adjusted to 1 × 10 ⁻⁵ Torr.
It was evacuated to.

(6-7) Next, RFi composed of a-Si
In order to form the mold layer 207, the gate valve 407 was opened to transfer the substrate to the transfer chamber 403 and the i-type layer deposition chamber 418 which were evacuated in advance by a vacuum exhaust pump (not shown). The back surface of the substrate was brought into close contact with the heater 411 for heating the substrate and heated, and the inside of the i-type layer deposition chamber 418 was evacuated to a pressure of about 1 × 10 ⁻⁵ Torr by a vacuum exhaust pump (not shown).

In order to form the RFi type layer, the substrate heating heater 411 is set so that the temperature of the substrate becomes 200 ° C., and when the substrate is sufficiently heated, the valves 464 and 45 are formed.
4, 450, 463, 453 are gradually opened and Si ₂ H ₆
Gas and H ₂ gas were caused to flow into the i-type layer deposition chamber 418 through the gas introduction pipe 449. At this time, the mass flow controllers 459 and 45 are controlled so that the Si ₂ H ₆ gas flow rate is ₂ sccm and the H ₂ gas flow rate is 80 sccm.
Adjusted at 8. The opening of a conductance valve (not shown) was adjusted so that the pressure in the i-type layer deposition chamber 418 became 0.6 Torr.

Next, the RF power source 424 is set to 0.007 W / c.
The RFi type layer is set on the RFn type layer 206 by setting it to m ² and applying it to the bias rod 428 to cause glow discharge and opening the shutter 427.
When the i-type layer of m was produced, the RF glow discharge was stopped,
The output of the RF power source 424 was turned off, and the fabrication of the RFi type layer 207 was completed. The valves 464, 454, 463, 453 are closed to stop the inflow of Si ₂ H ₆ gas and H ₂ gas into the i-type layer deposition chamber 418, the valve 450 is closed, and the inside of the i-type layer deposition chamber 418 and gas piping 1 x 10
Evacuated to ^-5 Torr.

(6-8) Next, RF composed of a-SiC
In order to form the p-type layer 208, the transfer chamber 4 previously evacuated by a vacuum exhaust pump (not shown).
04 and the p-type layer deposition chamber 419, the gate valve 408 was opened and the board | substrate was conveyed. The back surface of the substrate was brought into close contact with the substrate heating heater 412 and heated, 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 substrate is heated so that the temperature of the substrate becomes 170 ° C.
Set the heater for heat 412 and make sure that the substrate temperature is stable.
By the way, H₂Gas, SiH_Four/ H₂Gas, B₂H₆/ H₂gas,
CH _FourA gas is introduced into the deposition chamber 419 through a valve 481;
471, 470, 482, 472, 483, 473, 4
Operate 84, 474 and introduce through gas introduction pipe 469
did. At this time, H₂Gas flow rate is 60 sccm, SiH_Four/
H₂Gas flow rate is 2 sccm, B₂H₆/ H₂Gas flow rate is 10
sccm, CH_FourGas flow rate should be 0.3 sccm
Mass flow controllers 476, 477, 478,
The pressure in the deposition chamber 419 is adjusted to 2.
Conductance valve not shown so as to be 0 Torr
Adjusted the opening.

The power of the RF power source 423 is 0.07 W / cm ²
And RF power is introduced into the plasma forming cup 421 to cause glow discharge and R on the RFi type layer 207.
The formation of the Fp type layer was started, and when the RFp type layer having a layer thickness of 10 nm was formed, the RF power supply was turned off, the glow discharge was stopped, and the formation of the RFp type layer 208 was completed. Valve 472,
482, 473, 483, 474, 484, 471, 4
81 and 470 are closed, and SiH ₄ / H ₂ gas, B ₂ H ₆ / H ₂ gas, CH ₄ gas, and H are introduced into the p-type layer deposition chamber 419.
The inflow of ₂ gas was stopped, and the inside of the p-type layer deposition chamber 419 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

(7) Next, the gate valve 409 is opened into the unload chamber 405 which has been evacuated by a vacuum exhaust pump (not shown) in advance, the substrate is transferred, and a leak valve (not shown) is opened to unload the substrate. Chamber 4
05 leaked.

(8) Next, ITO having a layer thickness of 70 nm was vacuum-deposited on the RF p-type layer 208 as a transparent conductive layer 212 by a vacuum deposition method. (9) Next, a mask having comb-shaped holes is placed on the transparent conductive layer 212, and Cr (40 nm) / Ag (1000 nm) is placed.
A comb-shaped collector electrode 213 made of / Cr (40 nm) was vacuum-deposited by a vacuum deposition method.

With the above steps, the fabrication of the photovoltaic element of this example was completed. We decided to call this photovoltaic element (SC Ex 2). Further, an annealing treatment in a gas atmosphere containing a trace amount of oxygen atoms according to the present example, an RFn type layer, an RFi type layer, an MWi type layer,
The conditions for forming the RF p-type layer are shown in Tables 14 and 15.

Comparative Example 2-1 This example is different from Example 2 in that the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms was not performed.

Other points were the same as in Example 2. The photovoltaic element of this example is called (SC ratio 2-1).

Ten of each of the above-mentioned two types of photovoltaic elements (SC Ex 2) and (SC ratio 2-1) were produced. Table 2 shows the characteristics of initial photoelectric conversion efficiency (photovoltaic power / incident light power) and characteristic unevenness, photodegradation characteristics, environmental resistance characteristics in a high temperature and high humidity environment, and cross-sectional SEM observation for each of these photovoltaic elements. The evaluation results are obtained by measuring the adhesion.

Table 2 shows the results of the photovoltaic element (SC ratio 2-1), and the normalized results of the photovoltaic element (SC Ex 2) are shown.

[0210]

[Table 2] However, the characteristics of the initial photoelectric conversion efficiency were obtained by placing the manufactured photovoltaic element under AM-1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristics. The characteristic unevenness of the initial photoelectric conversion efficiency is a variation in the initial photoelectric conversion efficiency in each of the 10 photovoltaic elements.

The photodegradation characteristic means that the temperature of a photovoltaic element is 5
1000 at 1 m under 100 mW / cm ² at 0 ° C
It is the rate of decrease in the photoelectric conversion efficiency evaluated after irradiation for a period of time.

The environment resistance is defined as photoelectric conversion evaluated under an ambient temperature of 80 ° C., a humidity of 90%, and left in a dark place for 100 hours, then the temperature of the photovoltaic element is 25 ° C., and under 1 sun of 100 mW / cm ^2. This is the rate of decrease in efficiency.

The cross-section SEM observation is the result of evaluating the occurrence of microcracks on the cross section of the photovoltaic element using SEM (model number: S-4500, magnification: 50,000 times) manufactured by Hitachi, Ltd. As the microcracks, those having a size of 10 nm or more were measured, and the number of occurrence per unit area was measured.

The adhesion measurement is the result of observing the state of layer delamination with an Olympus optical microscope (bright field, 1000 times) with respect to the sample used for SEM observation of the cross section.

From the results in Table 2, the photovoltaic element of Example 2 (SC Ex 2) is superior to the photovoltaic element of Comparative Example 2-1 (SC ratio 2-1) in all evaluation results. I found out.

(Example 3) In this example, the triple photovoltaic element shown in FIG. 3 was produced using the in-line forming apparatus shown in FIG. The manufacturing method will be described below according to the procedure. (1) Reflective layer 3 prepared by the same method as in Example 1
01 and the substrate on which the reflection increasing layer 302 is formed are disposed on the substrate transfer rail 413 in the load chamber 401, and the load chamber 4 is loaded by a vacuum exhaust pump (not shown).
The inside of the chamber No. 01 was evacuated until the pressure reached about 1 × 10 ⁻⁵ Torr.

(2) Next, the transfer chamber 40 which has been evacuated by a vacuum exhaust pump (not shown) in advance.
The gate valves 406 and 407 were opened and transported into the chambers 2 and 403 and the deposition chamber 418. The back surface of the substrate is brought into close contact with the substrate heating heater 411 to heat it, and the pressure inside the deposition chamber 418 is adjusted to about 1 × by a vacuum exhaust pump (not shown).
It was evacuated to 10 ⁻⁵ Torr.

(3) After the preparation for film formation is completed as described above, H ₂ gas is introduced into the deposition chamber 417 through the gas introduction pipe 429, and the H ₂ gas flow rate is 500 sccc.
Open the valves 441, 431, 430 so that
It was adjusted with the mass flow controller 436. The pressure inside the deposition chamber 417 was adjusted to 1.3 Torr by a conductance valve (not shown). The substrate heating heater 410 was set so that the substrate temperature was 350 ° C., and when the substrate temperature became stable, the RFn-type layer 303 made of μc-Si was formed.

(4) Forming an RF n-type layer made of μc-Si
SiH_FourGas, PH_Three/ H ₂Cha depositing gas
Valves 443, 433, 444, 43
4 was operated and introduced through the gas introduction pipe 429. this
Sometimes SiH_FourGas flow rate is 2 sccm, H₂Gas flow rate is 10
0 sccm, PH_Three/ H₂The gas flow rate is 200 sccm
Mass flow controllers 438, 436, 4
39, and the pressure in the deposition chamber 417 is 1.3.
It was adjusted to be Torr.

The power of the RF power source 422 is 0.05 W / cm.
Set to ² , RF power is introduced into the plasma forming cup 420, glow discharge is generated, formation of the RFn type layer is started on the substrate, and the RF power source is turned off when the RFn type layer having a layer thickness of 20 nm is formed. Then, the glow discharge was stopped and the formation of the RFn type layer 303 was completed. Stop the inflow of SiH ₄ gas, PH ₃ / H ₂ gas, and H ₂ gas into the deposition chamber 417,
The deposition chamber and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

(5) Next, an annealing treatment was performed in a gas atmosphere containing a trace amount of oxygen atoms according to the present invention. To carry out the annealing treatment in the atmosphere of the gas containing a small amount of oxygen atoms of the present invention, O ₂ / Ar (dilution: 1
(00 ppm) gas was introduced into the deposition chamber 417 through a gas introduction pipe 429, and O ₂ / Ar (dilution degree: 100) was introduced.
(ppm) The valves 442 and 432 are opened so that the gas flow rate is 500 sccm, and the mass flow controller 43
Adjusted at 7. The pressure in the deposition chamber 417 is 1.3
The conductance valve (not shown) was used to adjust to Torr.

The heater 410 for heating the substrate was set so that the temperature of the substrate was 350 ° C., and the annealing treatment was performed for 10 minutes in the atmosphere of the gas containing a trace amount of oxygen atoms.
Next, O ₂ / Ar (dilution:
(100 ppm) gas is stopped and the deposition chamber 4
The inside of 17 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

(6) Next, in the same manner as in Example 2, the RFi type layer 351 made of a-Si and the a-SiGe are formed.
MWi type layer 304 made of a, RFi type layer 361 made of a-Si, RFp type layer 305 made of a-SiC, μc
RFn type layer 306 made of -Si, R made of a-Si
Fi-type layer 352, MWi-type layer 30 made of a-SiGe
7, RFi type layer 362 made of a-Si, RFp type layer 308 made of a-SiC, RFn type layer 309 made of μc-Si, RFi type layer 310 made of a-Si, aS
The RF p-type layer 311 made of iC was sequentially formed.

(7) Next, as a transparent conductive layer 312, ITO having a layer thickness of 70 nm was vacuum-deposited on the RF p-type layer 311 by a vacuum deposition method. (8) Next, a mask having comb-shaped holes is placed on the transparent conductive layer 312, and Cr (40 nm) / Ag (1000 nm) is placed.
A comb-shaped collector electrode 313 made of / Cr (40 nm) was vacuum-deposited by a vacuum deposition method.

The fabrication of the photovoltaic element of this example was completed above. This photovoltaic element is called (SC Ex 3). Further, an annealing treatment in a gas atmosphere containing a trace amount of oxygen atoms according to the present example, an RFn type layer, an RFi type layer, an MWi type layer,
The conditions for forming the RF p-type layer are shown in Tables 16 and 17.

(Comparative Example 3-1) This example is different from Example 3 in that the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms was not performed.

Other points were the same as in Example 3. The photovoltaic element of this example is called (SC ratio 3-1).

The above-mentioned two types of photovoltaic elements (SC Ex 3) and (SC ratio 3-1) were prepared in seven pieces each.
Table 3 shows the characteristics of the initial photoelectric conversion efficiency (photovoltaic power / incident light power) and the characteristic unevenness for each of these photovoltaic devices.
Photodegradation characteristics, environment resistance characteristics in high temperature and high humidity environment, cross section S
It is an evaluation result of EM observation and adhesion measurement.

Table 3 shows the results of the photovoltaic element (SC ratio 3-1), and the normalized results of the photovoltaic element (SC Ex 3) are shown.

[0230]

[Table 3] However, the characteristics of the initial photoelectric conversion efficiency were obtained by placing the manufactured photovoltaic element under AM-1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristics. The characteristic unevenness of the initial photoelectric conversion efficiency is a variation in the initial photoelectric conversion efficiency in each of the seven photovoltaic elements.

The photodegradation characteristic means that the temperature of the photovoltaic element is 5
1000 at 1 m under 100 mW / cm ² at 0 ° C
It is the rate of decrease in the photoelectric conversion efficiency evaluated after irradiation for a period of time.

[0232] The environment resistance is defined as photoelectric conversion evaluated under an ambient temperature of 80 ° C, a humidity of 90%, and left in a dark place for 150 hours, the temperature of the photovoltaic element is 25 ° C, and 100 mW / cm ² under 1 sun. This is the rate of decrease in efficiency.

The cross-section SEM observation is the result of evaluating the occurrence of microcracks on the cross section of the photovoltaic element using SEM (model number: S-4500, magnification: 50,000 times) manufactured by Hitachi, Ltd. As the microcracks, those having a size of 10 nm or more were measured, and the number of occurrence per unit area was measured.

The adhesion measurement is a result of observing the state of layer delamination with an optical microscope (bright field, 1000 times) manufactured by Olympus Corporation with respect to the sample used for the SEM observation of the cross section.

From the results shown in Table 3, the photovoltaic element of Example 3 (SC Ex 3) is superior to the photovoltaic element of Comparative Example 3-1 (SC ratio 3-1) in all evaluation results. I found out.

Example 4 In this example, instead of the RFn type layer 303 made of μc-Si, RFi made of a-Si is used.
The difference from Example 3 is that the mold layer 351 is annealed. Also in this example, the triple-type photovoltaic element shown in FIG. 3 was produced using the in-line forming apparatus shown in FIG. The manufacturing method will be described below according to the procedure.

(1) The substrate carrying rail 4 in the load chamber 401 is used for the substrate on which the reflection layer 301 and the reflection increasing layer 302 are formed, which is prepared by the same method as in the first embodiment.
13 and the inside of the load chamber 401 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

(2) Next, the transfer chamber 40 which has been evacuated by a vacuum exhaust pump (not shown) in advance.
The gate valves 406 and 407 were opened and transported into the chambers 2 and 403 and the deposition chamber 418. The back surface of the substrate is brought into close contact with the substrate heating heater 411 to heat it, and the pressure inside the deposition chamber 418 is adjusted to about 1 × by a vacuum exhaust pump (not shown).
It was evacuated to 10 ⁻⁵ Torr.

(3) After the preparation for film formation is completed as described above, H ₂ gas is introduced into the deposition chamber 417 through the gas introduction pipe 429, and the H ₂ gas flow rate is 500 sccc.
Open the valves 441, 431, 430 so that
It was adjusted with the mass flow controller 436. The pressure inside the deposition chamber 417 was adjusted to 1.3 Torr by a conductance valve (not shown). The substrate heating heater 410 is set so that the substrate temperature is 350 ° C., and when the substrate temperature is stable, the RFn-type layer 303 made of μc-Si and the RFi-type layer 351 made of a-Si.
Was formed.

(4) Next, an annealing treatment was performed in a gas atmosphere containing a trace amount of oxygen atoms according to the present invention. In order to perform the annealing treatment in the atmosphere of the gas containing a small amount of oxygen atoms of the present invention, as the oxygen atom containing gas, O ₂ / H ₂ (dilution: 1 p
pm) gas is introduced into the deposition chamber 418 through the gas introduction pipe 44
9 and introduced so that the O ₂ / H ₂ (dilution degree: 1 ppm) gas flow rate was 500 sccm.
5 was opened and adjusted with the mass flow controller 460. The pressure inside the deposition chamber 418 was adjusted to 1.0 Torr by a conductance valve (not shown).

The heater 411 for heating the substrate was set so that the temperature of the substrate became 300 ° C., and the annealing treatment in the atmosphere of the gas containing a small amount of oxygen atoms of the present invention was performed for 10 minutes.
Next, O ₂ / H ₂ (dilution: 1
(ppm) gas was stopped, and the inside of the deposition chamber 418 and the gas pipe was evacuated to 1 × 10 ⁻⁵ Torr.

(5) Next, by the same method as in Example 2, the MWi type layer 304 made of a-SiGe and the a-Si.
RFi-type layer 361 made of a, RFp made of a-SiC
Type layer 305, RFn type layer 306 made of μc-Si, a
-Si RFi type layer 352, a-SiGe MWi type layer 307, a-Si RFi type layer 36
2, RF p-type layer 308 made of a-SiC, μc-Si
The RFn type layer 309 made of a, the RFi type layer 310 made of a-Si, and the RFp type layer 311 made of a-SiC were sequentially formed.

(6) Next, on the RF p-type layer 311, as the transparent conductive layer 312, ITO having a layer thickness of 70 nm was vacuum-deposited by a vacuum deposition method. (7) Next, a mask having comb-shaped holes is placed on the transparent conductive layer 312, and Cr (40 nm) / Ag (1000 nm) is placed.
A comb-shaped collector electrode 313 made of / Cr (40 nm) was vacuum-deposited by a vacuum deposition method.

The fabrication of the photovoltaic element of this example was completed above. We decided to call this photovoltaic element (SC Ex 4). Further, an annealing treatment in a gas atmosphere containing a trace amount of oxygen atoms according to the present example, an RFn type layer, an RFi type layer, an MWi type layer,
The conditions for forming the RF p-type layer are shown in Tables 18 and 19.

(Comparative Example 4-1) This example differs from Example 4 in that the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms was not performed.

Other points were the same as in Example 4. The photovoltaic element of this example is called (SC ratio 4-1).

Eight pieces each of the above-mentioned two types of photovoltaic elements (SC Ex 4) and (SC ratio 4-1) were produced.
Table 4 shows the characteristics of the initial photoelectric conversion efficiency (photovoltaic power / incident light power) and the characteristic unevenness for each of these photovoltaic devices.
Photodegradation characteristics, environment resistance characteristics in high temperature and high humidity environment, cross section S
It is an evaluation result of EM observation and adhesion measurement.

Table 4 shows the results of the photovoltaic element (SC ratio 4-1), and the normalized results of the photovoltaic element (SC Ex 4) are shown.

[0249]

[Table 4] However, the characteristics of the initial photoelectric conversion efficiency were obtained by placing the manufactured photovoltaic element under AM-1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristics. The characteristic unevenness of the initial photoelectric conversion efficiency is a variation in the initial photoelectric conversion efficiency in each of the eight photovoltaic elements.

The photodegradation characteristic means that the temperature of the photovoltaic element is 5
1000 at 1 m under 100 mW / cm ² at 0 ° C
It is the rate of decrease in the photoelectric conversion efficiency evaluated after irradiation for a period of time.

The environment resistance is defined as the photoelectric conversion evaluated under an atmospheric temperature of 83 ° C., a humidity of 90%, a dark place for 150 hours, a photovoltaic element temperature of 25 ° C., and 100 mW / cm ² under 1 sun. This is the rate of decrease in efficiency.

The cross-section SEM observation is the result of evaluating the cross-section of the photovoltaic element using a SEM manufactured by Hitachi, Ltd. (model number: S-4500, magnification: 50,000 times) to evaluate the occurrence of microcracks. As the microcracks, those having a size of 10 nm or more were measured, and the number of occurrence per unit area was measured.

The adhesion measurement is the result of observing the state of layer delamination with an Olympus optical microscope (bright field, 1000 times) with respect to the sample used for the cross-section SEM observation.

From the results in Table 4, the photovoltaic element of Example 4 (SC Ex 4) was superior to the photovoltaic element of Comparative Example 4-1 (SC ratio 4-1) in all evaluation results. I found out.

(Embodiment 5) In the present embodiment, in place of the RFn type layer 303 made of μc-Si, M made of a-SiGe is used.
The difference from Example 3 is that the Wi-type layer 304 was subjected to an annealing treatment. Also in this example, the triple-type photovoltaic element shown in FIG. 3 was produced using the in-line forming apparatus shown in FIG. The manufacturing method will be described below according to the procedure.

(1) The substrate carrying rail 4 in the load chamber 401 is used for the substrate on which the reflection layer 301 and the reflection increasing layer 302 are formed, prepared by the same method as in the first embodiment.
13 and the inside of the load chamber 401 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

(2) Next, the transfer chamber 40 which has been evacuated by a vacuum exhaust pump (not shown) in advance.
The gate valves 406 and 407 were opened and transported into the chambers 2 and 403 and the deposition chamber 418. The back surface of the substrate is brought into close contact with the substrate heating heater 411 to heat it, and the pressure inside the deposition chamber 418 is adjusted to about 1 × by a vacuum exhaust pump (not shown).
It was evacuated to 10 ⁻⁵ Torr.

(3) After the preparation for film formation is completed as described above, H ₂ gas is introduced into the deposition chamber 417 through the gas introduction pipe 429, and the H ₂ gas flow rate is 500 sccc.
Open the valves 441, 431, 430 so that
It was adjusted with the mass flow controller 436. The pressure inside the deposition chamber 417 was adjusted to 1.3 Torr by a conductance valve (not shown).

The heater 410 for heating the substrate is set so that the temperature of the substrate becomes 350 ° C., and when the substrate temperature becomes stable, the RFn-type layer 303 made of μc-Si, a-Si.
RFi type layer 351 made of a, MW made of a-SiGe
The i-type layer 304 was formed.

(4) Next, an annealing treatment was performed in a gas atmosphere containing a trace amount of oxygen atoms according to the present invention. In order to perform the annealing treatment in the atmosphere of the gas containing a small amount of oxygen atoms of the present invention, O ₂ / He (dilution: 1
ppm) gas into the deposition chamber 418
Introduced through 49, O ₂ / He (dilution: 1 ppm)
A valve 465 so that the gas flow rate is 500 sccm,
455 was opened, and the mass flow controller 460 adjusted. The pressure in the deposition chamber 418 is 1.0 Torr
Was adjusted with a conductance valve (not shown).

The heater 411 for heating the substrate was set so that the temperature of the substrate was 300 ° C., and the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms of the present invention was performed for 10 minutes.
Next, O ₂ / He (dilution:
The flow of 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.

(5) Next, in the same manner as in Example 2, the RFi-type layer 361 made of a-Si, the RFp-type layer 305 made of a-SiC, the RFn-type layer 306 made of μc-Si, a- RFi type layer 352 made of Si, aS
MWi type layer 307 made of iGe, R made of a-Si
Fi-type layer 362, RFp-type layer 30 made of a-SiC
8. An RFn type layer 309 made of μc-Si, an RFi type layer 310 made of a-Si, and an RFp type layer 311 made of a-SiC were sequentially formed.

(6) Next, on the RF p-type layer 311, as the transparent conductive layer 312, ITO having a layer thickness of 70 nm was vacuum-deposited by a vacuum deposition method. (7) Next, a mask having comb-shaped holes is placed on the transparent conductive layer 312, and Cr (40 nm) / Ag (1000 nm) is placed.
A comb-shaped collector electrode 313 made of / Cr (40 nm) was vacuum-deposited by a vacuum deposition method.

The fabrication of the photovoltaic element of this example was completed above. This photovoltaic element is called (SC Ex 5). Further, an annealing treatment in a gas atmosphere containing a trace amount of oxygen atoms according to the present example, an RFn type layer, an RFi type layer, an MWi type layer,
The conditions for forming the RF p-type layer are shown in Tables 20 and 21.

(Comparative Example 5-1) This example is different from Example 5 in that the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms was not performed.

Other points were the same as in Example 5. The photovoltaic element of this example is called (SC ratio 5-1).

Eight pieces each of the above-mentioned two types of photovoltaic elements (SC Ex 5) and (SC ratio 5-1) were produced.
Table 5 shows the characteristics of the initial photoelectric conversion efficiency (photovoltaic power / incident light power) and the characteristic unevenness for each of these photovoltaic elements.
Photodegradation characteristics, environment resistance characteristics in high temperature and high humidity environment, cross section S
It is an evaluation result of EM observation and adhesion measurement.

Table 5 shows the results of the photovoltaic element (SC ratio 5-1), and the normalized results of the photovoltaic element (SC Ex 5) are shown.

[0269]

[Table 5] However, the characteristics of the initial photoelectric conversion efficiency were obtained by placing the manufactured photovoltaic element under AM-1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristics. The characteristic unevenness of the initial photoelectric conversion efficiency is a variation in the initial photoelectric conversion efficiency in each of the eight photovoltaic elements.

The photodegradation characteristic means that the temperature of the photovoltaic element is 5
1000 at 1 m under 100 mW / cm ² at 0 ° C
It is the rate of decrease in the photoelectric conversion efficiency evaluated after irradiation for a period of time.

The environment resistance is defined as photoelectric conversion evaluated under an atmospheric temperature of 83 ° C., a humidity of 90%, a dark place for 150 hours, a photovoltaic element temperature of 25 ° C., and 100 mW / cm ² under 1 sun. This is the rate of decrease in efficiency.

The cross-section SEM observation is the result of evaluating the cross-section of the photovoltaic element using a SEM manufactured by Hitachi, Ltd. (model number: S-4500, magnification: 50,000 times) to evaluate the occurrence of microcracks. As the microcracks, those having a size of 10 nm or more were measured, and the number of occurrence per unit area was measured.

The adhesion measurement is the result of observing the state of layer delamination with an Olympus optical microscope (bright field, 1000 times) with respect to the sample used for the cross-section SEM observation.

From the results of Table 5, the photovoltaic element of Example 5 (SC Ex 5) is superior to the photovoltaic element of Comparative Example 5-1 (SC ratio 5-1) in all evaluation results. I found out.

(Embodiment 6) In this example, instead of the RFn type layer 303 made of μc-Si, RFi made of a-Si is used.
The difference from Example 3 is that the mold layer 361 is annealed. Also in this example, the triple-type photovoltaic element shown in FIG. 3 was produced using the in-line forming apparatus shown in FIG. The manufacturing method will be described below according to the procedure.

(1) The substrate carrying rail 4 in the load chamber 401 is the substrate on which the reflective layer 301 and the reflection increasing layer 302 are formed, which is prepared by the same method as in the first embodiment.
13 and the inside of the load chamber 401 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

(2) Next, the transfer chamber 40 which has been evacuated by a vacuum exhaust pump (not shown) in advance.
The gate valves 406 and 407 were opened and transported into the chambers 2 and 403 and the deposition chamber 418. The back surface of the substrate is brought into close contact with the substrate heating heater 411 to heat it, and the pressure inside the deposition chamber 418 is adjusted to about 1 × by a vacuum exhaust pump (not shown).
It was evacuated to 10 ⁻⁵ Torr.

(3) After the preparation for film formation is completed as described above, H ₂ gas is introduced into the deposition chamber 417 through the gas introduction pipe 429, and the H ₂ gas flow rate is 500 sccc.
Open the valves 441, 431, 430 so that
It was adjusted with the mass flow controller 436. The pressure inside the deposition chamber 417 was adjusted to 1.3 Torr by a conductance valve (not shown). The substrate heating heater 410 is set so that the temperature of the substrate becomes 350 ° C., and when the substrate temperature becomes stable, the RFn-type layer 303 made of μc-Si and the RFi-type layer 35 made of a-Si.
1. MWi type layer 304 made of a-SiGe, a-Si
The RFi type layer 361 made of was formed.

(4) Next, an annealing treatment was performed in a gas atmosphere containing a trace amount of oxygen atoms according to the present invention. In order to perform the annealing treatment in the atmosphere of the gas containing a small amount of oxygen atoms of the present invention, O ₂ / Ar (dilution degree: 10) is used as the oxygen atom-containing gas.
0 ppm) gas was introduced into the deposition chamber 418 through the gas introduction pipe 449, and O ₂ / Ar (dilution degree: 100 p
pm) Valve 4 so that the gas flow rate is 500 sccm
Open 65 and 455, mass flow controller 460
Was adjusted. The pressure in the deposition chamber 418 is 1.2T
The conductance valve (not shown) was used to adjust the value to orr. The heater 411 for heating the substrate was set so that the temperature of the substrate became 300 ° C., and the annealing treatment in the atmosphere of the gas containing a small amount of oxygen atoms of the present invention was performed for 10 minutes. Next, O ₂ / Ar (dilution: 10) into the deposition chamber 418
(0 ppm) gas was stopped, and the inside of the deposition chamber 418 and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

(5) Next, in the same manner as in Example 2, the RF p-type layer 305 made of a-SiC and μc-Si are formed.
RF n-type layer 306 made of a-Si, RFi-type layer 352 made of a-Si, MWi-type layer 307 made of a-SiGe, a
RFi type layer 362 made of -Si, RFp type layer 308 made of a-SiC, RFn type layer 30 made of μc-Si.
9. An RFi type layer 310 made of a-Si and an RFp type layer 311 made of a-SiC were sequentially formed.

(6) Next, ITO having a layer thickness of 70 nm was vacuum-deposited on the RF p-type layer 311 as a transparent conductive layer 312 by a vacuum deposition method. (7) Next, a mask having comb-shaped holes is placed on the transparent conductive layer 312, and Cr (40 nm) / Ag (1000 nm) is placed.
A comb-shaped collector electrode 313 made of / Cr (40 nm) was vacuum-deposited by a vacuum deposition method.

With the above steps, the production of the photovoltaic element of this example was completed. We decided to call this photovoltaic element (SC Ex 6). Further, an annealing treatment in a gas atmosphere containing a trace amount of oxygen atoms according to the present example, an RFn type layer, an RFi type layer, an MWi type layer,
The conditions for forming the RF p-type layer are shown in Tables 22 and 23.

(Comparative Example 6-1) This example is different from Example 6 in that the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms was not performed.

Other points were the same as in Example 6. The photovoltaic element of this example is called (SC ratio 6-1).

The above-mentioned two types of photovoltaic elements (SC Ex 6) and (SC ratio 6-1) were prepared in 7 pieces each.
Table 6 shows the characteristics of the initial photoelectric conversion efficiency (photovoltaic power / incident light power) and the characteristic unevenness for each of these photovoltaic elements.
Photodegradation characteristics, environment resistance characteristics in high temperature and high humidity environment, cross section S
It is an evaluation result of EM observation and adhesion measurement.

Table 6 shows the results of the photovoltaic element (SC ratio 6-1), and the normalized results of the photovoltaic element (SC Ex 6) are shown.

[0287]

[Table 6] However, the characteristics of the initial photoelectric conversion efficiency were obtained by placing the manufactured photovoltaic element under AM-1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristics. The characteristic unevenness of the initial photoelectric conversion efficiency is a variation in the initial photoelectric conversion efficiency in each of the seven photovoltaic elements.

The photodegradation characteristic means that the temperature of the photovoltaic element is 5
1000 at 1 m under 100 mW / cm ² at 0 ° C
It is the rate of decrease in the photoelectric conversion efficiency evaluated after irradiation for a period of time.

The environment resistance is defined as photoelectric conversion evaluated under an ambient temperature of 83 ° C., a humidity of 90%, a dark place of 150 hours, a photovoltaic element temperature of 25 ° C., and 100 mW / cm ² under 1 sun. This is the rate of decrease in efficiency.

The cross-section SEM observation is the result of evaluating the occurrence of microcracks on the cross section of the photovoltaic element using SEM (model number: S-4500, magnification: 50,000 times) manufactured by Hitachi, Ltd. As the microcracks, those having a size of 10 nm or more were measured, and the number of occurrence per unit area was measured.

The adhesion measurement is a result of observing the state of layer delamination with an optical microscope (bright field, 1000 times) manufactured by Olympus Corporation with respect to the sample used for the cross-section SEM observation.

From the results in Table 6, the photovoltaic element of Example 6 (SC Ex 6) was superior to the photovoltaic element of Comparative Example 6-1 (SC ratio 6-1) in all evaluation results. I found out.

Example 7 In this example, instead of the RFn type layer 203 made of μc-Si, an RF made of a-SiC was used.
The difference from Example 2 is that the p-type layer 205 is annealed. In this example, the tandem photovoltaic element shown in FIG. 2 was produced using the in-line forming apparatus shown in FIG. The manufacturing method will be described below according to the procedure.

(1) The substrate carrying rail 4 in the load chamber 401 is used for the substrate on which the reflection layer 201 and the reflection increasing layer 202 are formed, which is prepared by the same method as in the first embodiment.
13 and the inside of the load chamber 401 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

(2) Next, the transfer chamber 402 which has been evacuated by a vacuum exhaust pump (not shown) in advance.
Then, the gate valve 406 was opened and conveyed into the deposition chamber 417. The back surface of the substrate is a heater 410 for heating the substrate.
Then, the deposition chamber 417 was evacuated to a pressure of about 1 × 10 ⁻⁵ Torr by a vacuum exhaust pump (not shown).

(3) After the preparation for film formation is completed as described above, H ₂ gas is introduced into the deposition chamber 417 through the gas introduction pipe 429, and the H ₂ gas flow rate is 500 sccc.
Open the valves 441, 431, 430 so that
It was adjusted with the mass flow controller 436. The pressure in the deposition chamber 417 was adjusted to 1.0 Torr by a conductance valve (not shown). The heater 410 for heating the substrate was set so that the temperature of the substrate was 350 ° C., and when the substrate temperature became stable, the RFn layer 203 made of μc-Si and a-S were formed by the same method as in Example 2.
RFi type layer 251 made of i, M made of a-SiGe
Wi-type layer 204, RFi-type layer 261 made of a-Si,
An RF p-type layer 205 made of a-SiC was formed.

(4) Next, an annealing treatment was performed in a gas atmosphere containing a trace amount of oxygen atoms according to the present invention. In order to perform the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms of the present invention, the oxygen atom containing gas is O ₂ / H ₂ (dilution degree: 10
(00 ppm) gas is introduced into the deposition chamber 417 through a gas introduction pipe 429, and O ₂ / H ₂ (dilution degree: 1000) is introduced.
(ppm) The valves 442 and 432 are opened so that the gas flow rate is 500 sccm, and the mass flow controller 43
Adjusted at 6. The pressure in the deposition chamber 417 is 1.0
The conductance valve (not shown) was used to adjust to Torr. The heater 410 for heating the substrate was set so that the temperature of the substrate was 225 ° C., and the annealing treatment was performed for 10 minutes in the atmosphere of the gas containing a trace amount of oxygen atoms. Next, O ₂ / H ₂ (dilution: 10) into the deposition chamber 417
(00 ppm) gas flow is stopped and deposition chamber 417
The inside and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

(5) Next, the RFn type layer 206 made of μc-Si, the RFi type layer 207 made of a-Si, and the RFp type layer 208 made of a-SiC are sequentially formed by the same method as in the second embodiment. did. (6) Next, the transparent conductive layer 212 is formed on the RF p-type layer 208.
As a film, ITO having a layer thickness of 70 nm was vacuum deposited by a vacuum deposition method.

(7) Next, a mask with comb-shaped holes is placed on the transparent conductive layer 212, and Cr (40 nm) / Ag (1
(000 nm) / Cr (40 nm), and a comb-shaped collector electrode 213 was vacuum deposited by a vacuum deposition method.

The fabrication of the photovoltaic element of this example was completed above. We decided to call this photovoltaic element (SC Ex 7). Further, an annealing treatment in a gas atmosphere containing a trace amount of oxygen atoms according to the present example, an RFn type layer, an RFi type layer, an MWi type layer,
The conditions for forming the RF p-type layer are shown in Tables 24 and 25.

(Comparative Example 7-1) This example is different from Example 7 in that the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms was not performed.

The other points were the same as in Example 7. The photovoltaic element of this example is called (SC ratio 7-1).

The above-mentioned two types of photovoltaic elements (SC Ex. 7) and (SC ratio 7-1) were produced in seven pieces each.
Table 7 shows the characteristics of the initial photoelectric conversion efficiency (photovoltaic power / incident light power) and the characteristic unevenness for each of these photovoltaic elements.
Photodegradation characteristics, environment resistance characteristics in high temperature and high humidity environment, cross section S
It is an evaluation result of EM observation and adhesion measurement.

Table 7 shows the results of the photovoltaic element (SC ratio 7-1), and the normalized results of the photovoltaic element (SC Ex 7) are shown.

[0305]

[Table 7] However, the characteristics of the initial photoelectric conversion efficiency were obtained by placing the manufactured photovoltaic element under AM-1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristics. The characteristic unevenness of the initial photoelectric conversion efficiency is a variation in the initial photoelectric conversion efficiency in each of the seven photovoltaic elements.

The photodegradation characteristic means that the temperature of the photovoltaic element is 5
1000 at 1 m under 100 mW / cm ² at 0 ° C
It is the rate of decrease in the photoelectric conversion efficiency evaluated after irradiation for a period of time.

The environment resistance is defined as photoelectric conversion evaluated under an atmosphere temperature of 84 ° C., a humidity of 90%, a dark place of 150 hours, a photovoltaic element temperature of 25 ° C., and 100 mW / cm ² under 1 sun. This is the rate of decrease in efficiency.

The cross-section SEM observation is the result of evaluating the occurrence of microcracks on the cross section of the photovoltaic element using SEM (model number: S-4500, magnification: 50,000 times) manufactured by Hitachi, Ltd. As the microcracks, those having a size of 10 nm or more were measured, and the number of occurrence per unit area was measured.

The adhesion measurement is a result of observing the state of layer delamination with an optical microscope (bright field, 1000 times) manufactured by Olympus Corporation with respect to the sample used for the cross-section SEM observation.

From the results in Table 7, the photovoltaic element of Example 7 (SC Ex 7) is superior to the photovoltaic element of Comparative Example 7-1 (SC ratio 7-1) in all evaluation results. I found out.

(Embodiment 8) In this embodiment, the concentration of the trace oxygen atom-containing gas used in the annealing treatment is 0.3 ppm to
This example differs from Example 3 in that the influence on the initial characteristics of photoelectric conversion was investigated by changing the range of 2000 ppm. H ₂ gas was used as a diluent gas for determining the concentration of the trace oxygen atom-containing gas.

Table 26 shows annealing treatment conditions, and Table 27.
Shows the manufacturing conditions of the triple photovoltaic element. Also in this example, the triple-type photovoltaic element shown in FIG. 3 was produced using the in-line forming apparatus shown in FIG. Other points were the same as in Example 3.

Table 28 shows the evaluation results of the photovoltaic element of this example evaluated in the same manner as in Example 3. The evaluation result of each characteristic in Table 28 shows that the trace oxygen atom-containing gas concentration is 0.3.
In the case of ppm, the results are standardized and shown. ×
The mark is 1.0 to less than 1.4, and the △ mark is 1.4 to 1.8.
Less than, and ○ indicates 1.8 or more.

From Table 28, the oxygen atom-containing gas concentration in the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms was H ₂
It has been found that 1 ppm to 1000 ppm is a suitable concentration with respect to the gas in terms of characteristics and unevenness of characteristics of the photovoltaic element, photodegradation characteristics, environment resistance characteristics in a high temperature and high humidity environment, and adhesion.

(Embodiment 9) In this embodiment, the concentration of the trace oxygen atom-containing gas used in the annealing treatment is 0.3 ppm to
This example differs from Example 3 in that the influence on the initial characteristics of photoelectric conversion was investigated by changing the range of 2000 ppm. He gas was used as a diluent gas for determining the concentration of the trace oxygen atom-containing gas.

Table 29 shows the annealing conditions and Table 30.
Shows the manufacturing conditions of the triple photovoltaic element. Also in this example, the triple-type photovoltaic element shown in FIG. 3 was produced using the in-line forming apparatus shown in FIG. Other points were the same as in Example 3.

Table 31 shows the evaluation results of the photovoltaic device of this example evaluated in the same manner as in Example 3. The evaluation result of each characteristic in Table 31 shows that the trace oxygen atom-containing gas concentration is 0.3.
In the case of ppm, the results are standardized and shown. ×
The mark is 1.0 to less than 1.4, and the △ mark is 1.4 to 1.8.
Less than, and ○ indicates 1.8 or more.

From Table 31, the oxygen atom-containing gas concentration in the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms is He.
It has been found that 1 ppm to 1000 ppm is a suitable concentration with respect to the gas in terms of characteristics and unevenness of characteristics of the photovoltaic element, photodegradation characteristics, environment resistance characteristics in a high temperature and high humidity environment, and adhesion.

Example 10 In this example, the concentration of the trace oxygen atom-containing gas used in the annealing treatment was 0.3 ppm.
It differs from Example 3 in that the influence on the initial characteristics of photoelectric conversion and the like was examined by changing it in the range of up to 2000 ppm. Ar gas was used as a diluent gas for determining the concentration of the trace oxygen atom-containing gas.

Table 32 shows annealing treatment conditions, and Table 33.
Shows the manufacturing conditions of the triple photovoltaic element. Also in this example, the triple-type photovoltaic element shown in FIG. 3 was produced using the in-line forming apparatus shown in FIG. Other points were the same as in Example 3.

Table 34 shows the evaluation results of the photovoltaic element of this example evaluated in the same manner as in Example 3. The evaluation result of each characteristic in Table 34 shows that the trace oxygen atom-containing gas concentration is 0.3.
In the case of ppm, the results are standardized and shown. ×
The mark is 1.0 to less than 1.4, and the △ mark is 1.4 to 1.8.
Less than, and ○ indicates 1.8 or more.

From Table 34, the oxygen atom-containing gas concentration in the annealing treatment in the trace oxygen atom-containing gas atmosphere is Ar.
It has been found that 1 ppm to 1000 ppm is a suitable concentration with respect to the gas in terms of characteristics and unevenness of characteristics of the photovoltaic element, photodegradation characteristics, environment resistance characteristics in a high temperature and high humidity environment, and adhesion.

Example 11 This example is different from Example 3 in that the temperature of the annealing treatment was changed in the range of 25 ° C. to 500 ° C. and the effect on the initial characteristics of photoelectric conversion was examined. H ₂ gas was used as a diluent gas for determining the concentration of the trace oxygen atom-containing gas.

Table 35 shows annealing treatment conditions, and Table 36
Shows the manufacturing conditions of the triple photovoltaic element. Also in this example, the triple-type photovoltaic element shown in FIG. 3 was produced using the in-line forming apparatus shown in FIG. Other points were the same as in Example 3.

Table 37 shows the evaluation results of the photovoltaic element of this example evaluated in the same manner as in Example 3. The evaluation results of each property in Table 37 are shown by standardizing the measurement results obtained when the annealing temperature is 25 ° C. The cross mark is 1.
0 or more and less than 1.4, △ mark is 1.4 or more and less than 1.8,
A circle indicates 1.8 or more.

From Table 37, the temperature of the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms was 50 ° C. in the characteristics and unevenness of characteristics of the photovoltaic element, the photodegradation characteristics, the environment resistance characteristics in the high temperature and high humidity environment, and the adhesion. ~ 400 ° C was found to be a suitable temperature.

Example 12 This example is different from Example 3 in that the pressure of the annealing treatment was changed in the range of 0.002 Torr to 100 Torr and the effect on the initial characteristics of photoelectric conversion was examined. H ₂ gas was used as a diluent gas for determining the concentration of the trace oxygen atom-containing gas.

Table 38 shows annealing conditions, and Table 39
Shows the manufacturing conditions of the triple photovoltaic element. Also in this example, the triple-type photovoltaic element shown in FIG. 3 was produced using the in-line forming apparatus shown in FIG. Other points were the same as in Example 3.

Table 40 shows the evaluation results of the photovoltaic element of this example evaluated in the same manner as in Example 3. The evaluation result of each property in Table 40 shows that the pressure of the annealing treatment is 0.00.
In the case of 2 Torr, the measurement results obtained are normalized and shown. The mark x indicates 1.0 or more and less than 1.4, the mark Δ indicates 1.4 or more and less than 1.8, and the mark ◯ indicates 1.8 or more.

From Table 40, the pressure of the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms is 0 in the characteristics and unevenness of characteristics of the photovoltaic element, the light deterioration characteristics, the environment resistance characteristics in the high temperature and high humidity environment, and the adhesion. .01 Torr to 10T
It has been found that orr is a suitable pressure.

(Example 13) This example is different from Example 3 in that the influence on the initial characteristics of photoelectric conversion was examined by changing the following three points (a) to (c). (A) MWi type layer 304 made of a-SiGe and a-
The microwave frequency in the case of forming the MWi-type layer 307 made of SiGe was changed in the range of 0.02 GHz to 50 GHz. (B) As the diluting gas for determining the concentration of the trace oxygen atom-containing gas, He gas was used instead of Ar gas. (C) The annealing treatment conditions for the MWi type layer 304 made of a-SiGe and the annealing treatment condition for the MWi type layer 307 made of a-SiGe were changed.

In this example, the triple photovoltaic element shown in FIG. 3 was produced using the in-line forming apparatus shown in FIG. The manufacturing method will be described below according to the procedure.

(1) The substrate having the reflective layer 301 and the reflection increasing layer 302 prepared by the same method as in Example 1 is used as the substrate transport rail 4 in the load chamber 401.
13 and the inside of the load chamber 401 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

(2) Next, the transfer chamber 40 which has been evacuated by a vacuum exhaust pump (not shown) in advance.
The gate valves 406 and 407 were opened and transported into the chambers 2 and 403 and the deposition chamber 418. The back surface of the substrate is brought into close contact with the substrate heating heater 411 to heat it, and the pressure inside the deposition chamber 418 is adjusted to about 1 × by a vacuum exhaust pump (not shown).
It was evacuated to 10 ⁻⁵ Torr.

(3) After the preparation for film formation is completed as described above, H ₂ gas is introduced into the deposition chamber 417 through the gas introduction pipe 429, and the H ₂ gas flow rate is 500 sccc.
Open the valves 441, 431, 430 so that
It was adjusted with the mass flow controller 436. The pressure inside the deposition chamber 417 was adjusted to 1.3 Torr by a conductance valve (not shown). The substrate heating heater 410 was set so that the substrate temperature was 350 ° C., and when the substrate temperature became stable, the RFn type -303, a-S made of μc-Si was prepared by the same method as in Example 2.
RFi type layer 351 made of i, M made of a-SiGe
The Wi-type layer 304 was formed. When forming the MWi type layer, the MW introducing window 425 was removed and an antenna type MW introducing electrode (not shown) was used depending on the frequency.

(4) Next, an annealing treatment was performed in a gas atmosphere containing a trace amount of oxygen atoms according to the present invention. In order to perform the annealing treatment in the atmosphere of the gas containing a small amount of oxygen atoms of the present invention, O ₂ / He (dilution: 1
ppm) gas into the deposition chamber 418
Introduced through 49, O ₂ / He (dilution: 1 ppm)
A valve 465 so that the gas flow rate is 500 sccm,
455 was opened, and the mass flow controller 460 adjusted. The pressure in the deposition chamber 418 is 1.0 Torr
Was adjusted with a conductance valve (not shown). The heater 411 for heating the substrate was set so that the temperature of the substrate became 300 ° C., and the annealing treatment in the atmosphere of the gas containing a small amount of oxygen atoms of the present invention was performed for 10 minutes. Next, O ₂ / He (dilution: 1 pp into the deposition chamber 418)
m) The gas inflow was stopped, and the inside of the deposition chamber 418 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

(5) Next, in the same manner as in Example 2, the RFi type layer 361 made of a-Si, the RFp type layer 305 made of a-SiC, the RFn type layer 306 made of μc-Si, a- RFi type-352, aS made of Si
The MWi-type layer 307 made of iGe was sequentially formed. MW
At the time of forming the i-type layer, the MW introduction window 425 was removed and an antenna type MW introduction electrode (not shown) was used depending on the frequency.

(6) Next, an annealing treatment was performed in a gas atmosphere containing a trace amount of oxygen atoms according to the present invention. In order to perform the annealing treatment in the atmosphere of the gas containing a small amount of oxygen atoms of the present invention, O ₂ / He (dilution: 1
ppm) gas into the deposition chamber 418
Introduced through 49, O ₂ / He (dilution: 1 ppm)
A valve 465 so that the gas flow rate is 500 sccm,
455 was opened, and the mass flow controller 460 adjusted. The pressure in the deposition chamber 418 is 1.5 Torr
Was adjusted with a conductance valve (not shown). The heater 411 for heating the substrate was set so that the temperature of the substrate was 280 ° C., and the annealing treatment was performed in the atmosphere of the gas containing a small amount of oxygen atoms of the present invention for 10 minutes. Next, O ₂ / He (dilution: 1 pp into the deposition chamber 418)
m) The gas inflow was stopped, and the inside of the deposition chamber 418 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

(7) Next, in the same manner as in Example 2, the RFi type layer 362 made of a-Si, the RFp type -308 made of a-SiC, and the RFn type layer 309 made of μc-Si, a-. RFi type layer 310 made of Si, aS
The RF p-type layer 311 made of iC was sequentially formed.

(8) Next, ITO having a layer thickness of 70 nm was vacuum-deposited on the RF p-type layer 311 as a transparent conductive layer 312 by a vacuum deposition method. (9) Next, a mask having comb-shaped holes is placed on the transparent thin electric layer 312, and Cr (40 nm) / Ag (1000 nm) is applied.
A comb-shaped collector electrode 313 made of / Cr (40 nm) was vacuum-deposited by a vacuum deposition method.

The fabrication of the photovoltaic element of this example was completed above. Annealing treatment in a gas atmosphere containing a trace amount of oxygen atoms, RFn type layer, RFi type layer, MWi type layer, RFp
The conditions for forming the mold layer are shown in Tables 41 and 42.

Table 43 shows the evaluation results of the photovoltaic element of this example evaluated in the same manner as in Example 3. The evaluation result of each characteristic in Table 43 shows that the microwave frequency is 0.02 GHz.
In the case of z, the measurement results obtained are normalized and shown. The mark x indicates 1.0 or more and less than 1.4, the mark Δ indicates 1.4 or more and less than 1.8, and the mark ◯ indicates 1.8 or more.

From Table 43, the microwave frequency when forming the MWi-type layer 304 made of a-SiGe and the MWi-type layer 307 made of a-SiGe, which is subjected to the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms, is 0.1G in the characteristics and unevenness of characteristics of the photovoltaic element, the light deterioration characteristics, the environment resistance characteristics in a high temperature and high humidity environment, and the adhesion.
It has been found that a frequency of 10 Hz to 10 GHz is a suitable frequency.

Example 14 In this example, the triple type photovoltaic element shown in FIG. 3 was produced by using the roll-to-roll type forming apparatus shown in FIG. At that time, the combination of annealing treatment conditions in the gas atmosphere containing a trace amount of oxygen atoms consisting of four kinds shown in Table 45 was changed. The manufacturing method will be described below according to the procedure.

(1) A sheet-like substrate (sheet width of 30 cm) having a reflective layer of Ag (or Al-Si or the like) and a reflection increasing layer of ZnO or the like formed on a stainless steel support is wound into a roll to obtain a sheet-like substrate. It was set in a loading chamber 5010 for introduction. (2) The sheet-shaped substrate was connected to the sheet winding jig in the unload chamber 5150 through the entire stacking chamber and all gas gates.

(3) Each of the deposition chambers is provided with an exhaust device (not shown).
^The gas was evacuated to ^-3 Torr or less. Mixing devices 5024, 5034, 5044, 5054, 50 for forming each deposited film
64, 5074, 5084, 5094, 5104, 51
A desired source gas was supplied to each deposition chamber from 14, 5124, 5134, and 5144.

(4) Each gas gate 5201, 5202,
5203, 5204, 5205, 5206, 5207,
5208, 5209, 5210, 5211, 5212,
The gas containing trace amounts of oxygen atoms of the present invention was supplied to the gas gates 5213 and 5214 from the respective gate gas supply devices (Table 44).

In the present embodiment, the interval at which the gas gate passes through the sheet-shaped substrate was made variable, so that the trace oxygen atom-containing gas of the present invention was flown to each gas gate so that the total flow rate was 1000 sccm. Further, the annealing temperature in the gas atmosphere containing a trace amount of oxygen atoms of the present invention is set to 350 ° C. to 50 ° C. by a heater in a gas gate (not shown)
C., and the annealing treatment pressure of the present invention was adjusted to 3 Torr to 1 Torr by an operating exhaust device (not shown).

(5) The substrate is heated by the heater for heating the substrate of each deposition apparatus, the opening / closing degree of the exhaust valve of each exhaust apparatus is adjusted to the vacuum degree, and after the substrate temperature and the vacuum degree are stabilized, the sheet The RF power for generating plasma and MW (frequency: 2.45 GHz) power were supplied to each deposition chamber, including the transportation of the substrate.

As described above, p is put on the sheet substrate 300.
A triple solar cell in which three in structures are stacked was formed.

(6) Next, ITO having a layer thickness of 70 nm was vacuum-deposited on the RF p-type layer 311 as a transparent conductive layer 312 by a vacuum deposition method. (7) Next, a mask having comb-shaped holes is placed on the transparent conductive layer 312, and Cr (40 nm) / Ag (1000 nm) is placed.
A comb-shaped collector electrode 313 made of / Cr (40 nm) was vacuum-deposited by a vacuum deposition method.

The fabrication of the photovoltaic element of this example was completed above. This photovoltaic element is called (SC Ex 14). Further, an annealing treatment in a gas atmosphere containing a trace amount of oxygen atoms according to the present example, an RFn type layer, an RFi type layer, an MWi type layer,
The conditions for forming the RF p-type layer are shown in Tables 44 and 45.

Comparative Example 14-1 This example is different from Example 14 in that desired H ₂ gas or He gas was supplied to each gas gate without performing annealing treatment in a gas atmosphere containing a trace amount of oxygen atoms. .

Other points were the same as in Example 14. The photovoltaic element of this example is called (SC ratio 14-1).

The above-mentioned two types of photovoltaic elements (SC Ex. 1
4) and (SC ratio 14-1) were produced seven each. Table 8 shows the characteristics of initial photoelectric conversion efficiency (photovoltaic power / incident optical power) and characteristic unevenness, photodegradation characteristics, environmental resistance characteristics in high temperature and high humidity environment, and cross-sectional SEM observation for each of these photovoltaic elements. The evaluation results are obtained by measuring the adhesion.

Table 8 shows the photovoltaic element (SC ratio 14-1).
The results of the photovoltaic element (SC Ex. 14) are standardized and shown.

[0357]

[Table 8] However, the characteristics of the initial photoelectric conversion efficiency were obtained by placing the manufactured photovoltaic element under AM-1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristics. The characteristic unevenness of the initial photoelectric conversion efficiency is a variation in the initial photoelectric conversion efficiency in each of the seven photovoltaic elements.

The photodegradation characteristic means that the temperature of the photovoltaic element is 5
1000 at 1 m under 100 mW / cm ² at 0 ° C
It is the rate of decrease in the photoelectric conversion efficiency evaluated after irradiation for a period of time.

The environment resistance is defined as the photoelectric conversion evaluated under an atmosphere temperature of 85 ° C., a humidity of 90%, and left in a dark place for 150 hours, then the temperature of the photovoltaic element is 25 ° C., and under 1 sun of 100 mW / cm ^2. This is the rate of decrease in efficiency.

The cross-section SEM observation is the result of evaluating the cross-section of the photovoltaic element using a SEM manufactured by Hitachi, Ltd. (model number: S-4500, magnification: 50,000 times) to evaluate the occurrence of microcracks. As the microcracks, those having a size of 10 nm or more were measured, and the number of occurrence per unit area was measured.

The adhesion measurement is a result of observing the state of layer delamination with an optical microscope (bright field, 1000 times) manufactured by Olympus Corporation with respect to the sample used for SEM observation of the cross section.

From the results in Table 8, the photovoltaic element of Example 14 (SC Ex 14) was superior to the photovoltaic element of Comparative Example 14-1 (SC ratio 14-1) in all evaluation results. I found out.

Example 15 In this example, the triple photovoltaic element shown in FIG. 3 was produced using the roll-to-roll system forming apparatus shown in FIG. At that time, the combination of annealing treatment conditions in the gas atmosphere containing a trace amount of oxygen atoms composed of four kinds shown in Table 47 was changed. The manufacturing method will be described below according to the procedure.

(1) A sheet-like substrate (sheet width 30 cm) having a reflective layer of Ag (or Al-Si or the like) and a reflection increasing layer of ZnO or the like formed on a stainless steel support was wound into a roll, and the sheet-like substrate It was set in a loading chamber 5010 for introduction. The sheet-shaped substrate was connected to the sheet winding jig of the unload chamber 5150 through the entire stacking chamber and all the gas gates, and each deposition chamber was exhausted to 10 ⁻³ Torr or less by an exhaust device (not shown).

(2) Mixing device 5 for forming each deposited film
024, 5034, 5044, 5054, 5064, 5
074, 5084, 5094, 5104, 5114, 5
A desired source gas was supplied to each deposition chamber from 124, 5134, and 5144.

(3) Each gas gate 5201, 5202,
5203, 5204, 5205, 5206, 5207,
5208, 5209, 5210, 5211, 5212,
A trace oxygen atom-containing gas of the present invention was supplied to each gas gate from 5213 and 5214 from each gate gas supply device (Table 46).

In this embodiment, since the interval at which the gas gate passes through the sheet-shaped substrate was made variable, the trace oxygen atom-containing gas of the present invention was flowed to each gas gate so that the total flow rate was 1000 sccm. Further, the annealing temperature in the gas atmosphere containing a trace amount of oxygen atoms of the present invention is set to 350 ° C. to 25 ° C. by a heater in a gas gate (not shown)
The pressure was adjusted to 0 ° C., and the annealing treatment pressure of the present invention was adjusted to 3 Torr to 1 Torr by an operating exhaust device (not shown).

(4) The substrate is heated by the heater for heating the substrate of each deposition apparatus, and the degree of opening and closing of the exhaust valve of each exhaust apparatus is adjusted to the degree of vacuum to stabilize the substrate temperature and the degree of vacuum. The RF power for generating plasma and MW (frequency: 0.5 GHz) power were supplied to each deposition chamber, including the transportation of the substrate. The MW power supply unit used an antenna type MW introduction electrode.

As described above, p is put on the sheet substrate 300.
A triple solar cell in which three in structures are stacked was formed.

(5) Next, as the transparent conductive layer 312, ITO having a layer thickness of 70 nm was vacuum-deposited on the RF p-type layer 311 by a vacuum deposition method. (6) Next, a mask with comb-shaped holes is placed on the transparent conductive layer 312, and Cr (40 nm) / Ag (1000 nm) is placed.
A comb-shaped collector electrode 313 made of / Cr (40 nm) was vacuum-deposited by a vacuum deposition method.

The fabrication of the photovoltaic element of this example was completed above. This photovoltaic element is called (SC Ex 15). Further, an annealing treatment in a gas atmosphere containing a trace amount of oxygen atoms according to the present example, an RFn type layer, an RFi type layer, an MWi type layer,
The conditions for forming the RF p-type layer are shown in Tables 46 and 47.

Comparative Example 15-1 In this example, the point that the desired H ₂ gas, He gas, or Ar gas was supplied to each gas gate without performing the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms was carried out. Different from Example 15.

Other points were the same as in Example 15. The photovoltaic element of this example is called (SC ratio 15-1).

The above-mentioned two types of photovoltaic elements (SC Ex. 1
5) and (SC ratio 15-1) were prepared in seven pieces each. Table 9 shows the characteristics of the initial photoelectric conversion efficiency (photovoltaic power / incident light power) and characteristic unevenness, photodegradation characteristics, environmental resistance characteristics in a high temperature and high humidity environment, and cross-sectional SEM observation for each of these photovoltaic elements. The evaluation results are obtained by measuring the adhesion.

Table 9 shows a photovoltaic element (SC ratio 15-1).
The results of the photovoltaic element (SC Ex. 15) are standardized and shown.

[0376]

[Table 9] However, the characteristics of the initial photoelectric conversion efficiency were obtained by placing the manufactured photovoltaic element under AM-1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristics. The characteristic unevenness of the initial photoelectric conversion efficiency is a variation in the initial photoelectric conversion efficiency in each of the seven photovoltaic elements.

The photodegradation characteristic means that the temperature of the photovoltaic element is 4
1000 at 1 m under 100 mW / cm ² at 8 ° C
It is the rate of decrease in the photoelectric conversion efficiency evaluated after irradiation for a period of time.

Environmental resistance is defined as photoelectric conversion evaluated under an ambient temperature of 87 ° C., a humidity of 90%, and left in a dark place for 200 hours, then the temperature of the photovoltaic element is 25 ° C., and under 1 sun of 100 mW / cm ^2. This is the rate of decrease in efficiency.

The cross-section SEM observation is a result of evaluating the cross-section of the photovoltaic element using a SEM manufactured by Hitachi, Ltd. (model number: S-4500, magnification: 50,000 times) for the occurrence of microcracks. As the microcracks, those having a size of 10 nm or more were measured, and the number of occurrence per unit area was measured.

The adhesion measurement is the result of observing the state of layer delamination with an Olympus optical microscope (bright field, 1000 times) for the sample used for the SEM observation of the cross section.

From the results in Table 9, the photovoltaic element of Example 15 (SC Ex. 15) is superior to the photovoltaic element of Comparative Example 15-1 (SC ratio 15-1) in all evaluation results. I found out.

(Example 16) In this example, the triple type photovoltaic element shown in FIG. 3 was produced by using the roll-to-roll type forming apparatus shown in FIG. At that time, the combination of annealing treatment conditions in the gas atmosphere containing a trace amount of oxygen atoms consisting of four kinds shown in Table 49 was changed. The manufacturing method will be described below according to the procedure.

(1) A sheet-like substrate (sheet width 30 cm) having a reflective layer of Ag (or Al-Si etc.) and a reflection-increasing layer of ZnO etc. formed on a stainless steel support was wound into a roll, and the sheet-like substrate was obtained. It was set in a loading chamber 5010 for introduction. The sheet-shaped substrate was connected to the sheet winding jig of the unload chamber 5150 through the entire stacking chamber and all the gas gates, and each deposition chamber was exhausted to 10 ⁻³ Torr or less by an exhaust device (not shown).

(2) Mixing device 5 for forming each deposited film
024, 5034, 5044, 5054, 5064, 5
074, 5084, 5094, 5104, 5114, 5
A desired source gas was supplied to each deposition chamber from 124, 5134, and 5144.

(3) Each gas gate 5201, 5202,
5203, 5204, 5205, 5206, 5207,
5208, 5209, 5210, 5211, 5212,
The gas containing trace amounts of oxygen atoms of the present invention was supplied to each of the gas gates 5213 and 5214 from each gate gas supply device (Table 48).

In the present embodiment, the interval at which the gas gate passes through the sheet-shaped substrate was made variable, so that the trace oxygen atom-containing gas of the present invention was flowed to each gas gate at a total flow rate of 1200 sccm. Further, the annealing temperature in the gas atmosphere containing a trace amount of oxygen atoms of the present invention is set to 350 ° C. to 50 ° C. by a heater in a gas gate (not shown)
C., and the annealing treatment pressure of the present invention was adjusted to 3 Torr to 1 Torr by an operating exhaust device (not shown).

(4) The substrate is heated by the heater for heating the substrate of each deposition apparatus, and the degree of opening and closing of the exhaust valve of each exhaust apparatus is adjusted to the degree of vacuum to stabilize the substrate temperature and degree of vacuum. The RF power for generating plasma and MW (frequency: 0.1 GHz) power were supplied to each deposition chamber, including the transportation of the substrate. The MW power supply unit used an antenna type MW introduction electrode.

As described above, p is put on the sheet substrate 300.
A triple solar cell in which three in structures are stacked was formed.

(5) Next, as the transparent conductive layer 312, ITO having a layer thickness of 70 nm was vacuum-deposited on the RF p-type layer 311 by a vacuum deposition method. (6) Next, a mask with comb-shaped holes is placed on the transparent conductive layer 312, and Cr (40 nm) / Ag (1000 nm) is placed.
A comb-shaped collector electrode 313 made of / Cr (40 nm) was vacuum-deposited by a vacuum deposition method.

The fabrication of the photovoltaic element of this example was completed above. This photovoltaic element is called (SC Ex 16). Further, an annealing treatment in a gas atmosphere containing a trace amount of oxygen atoms according to the present example, an RFn type layer, an RFi type layer, an MWi type layer,
The conditions for forming the RF p-type layer are shown in Tables 48 and 49.

(Comparative Example 16-1) In this example, the point that the desired H ₂ gas, He gas, or Ar gas was supplied to each gas gate without performing the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms was carried out. Different from Example 16.

The other points were the same as in Example 16. The photovoltaic element of this example is called (SC ratio 16-1).

The above-mentioned two types of photovoltaic elements (SC Ex. 1
6) and (SC ratio 16-1) were prepared in seven pieces each.
Table 10 shows the characteristics of the initial photoelectric conversion efficiency (photovoltaic power / incident light power) and characteristic unevenness, photodegradation characteristics, environmental resistance characteristics in high temperature and high humidity environment, and cross-sectional SEM observation for each of these photovoltaic elements. The evaluation results are obtained by measuring the adhesion.

Table 10 shows the photovoltaic device (SC ratio 16-
In the result of 1), the result of the photovoltaic element (SC Ex 16) is standardized and shown.

[0395]

[Table 10] However, the characteristics of the initial photoelectric conversion efficiency were obtained by placing the manufactured photovoltaic element under AM-1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristics. The characteristic unevenness of the initial photoelectric conversion efficiency is a variation in the initial photoelectric conversion efficiency in each of the seven photovoltaic elements.

The photodegradation characteristic means that the temperature of the photovoltaic element is 4
1000 at 1 m under 100 mW / cm ² at 5 ° C.
It is the rate of decrease in the photoelectric conversion efficiency evaluated after irradiation for a period of time.

The environment resistance is defined as photoelectric conversion evaluated under an atmosphere temperature of 86 ° C., a humidity of 91%, left in a dark place for 220 hours, then the temperature of the photovoltaic element is 25 ° C., and under 1 sun of 100 mW / cm ^2. This is the rate of decrease in efficiency.

The cross-section SEM observation is a result of evaluating the cross-section of the photovoltaic element using a SEM manufactured by Hitachi, Ltd. (model number: S-4500, magnification: 50,000 times) to evaluate the occurrence of microcracks. As the microcracks, those having a size of 10 nm or more were measured, and the number of occurrence per unit area was measured.

The adhesion measurement is a result of observing the state of layer delamination with an optical microscope (bright field, 1000 times) manufactured by Olympus Corporation with respect to the sample used for SEM observation of the cross section.

From the results in Table 10, the photovoltaic element of Example 16 (SC Ex 16) was superior to the photovoltaic element of Comparative Example 16-1 (SC ratio 16-1) in all evaluation results. I found out.

(Example 17) In this example, four kinds of single films for measuring the interface defect density were prepared using the in-line forming apparatus shown in FIG. The four types of samples are RFn type layers (Sample A), RFi type layers (Sample B), MWi type layers (Sample C), and RFp type single semiconductor layers formed. In the case of layers (Sample D).

The manufacturing method will be described below according to the procedure. (1) First, a substrate was manufactured. Thickness 0.8 mm, 2
A 5 × 50 mm ² quartz glass support (100) was ultrasonically cleaned with acetone and isopropanol and dried with warm air.

(2) Cr having a layer thickness of 5 nm was formed on the surface of the support (100) made of quartz glass at room temperature by the sputtering method.
Then, the production of the substrate was completed. (3) Next, 1 μm each of the semiconductor layers n, i, and p is formed by the same method as in Example 1, and the same method as in Example 1 is performed in an atmosphere containing a trace amount of oxygen atom-containing gas of the present invention. Processed.

Thus, the production of the single film for measuring the interface defect density of this example was completed. This single film for measuring the interface defect density is called (SC Ex 17). Tables 50 and 51 show the annealing conditions in the gas atmosphere containing a small amount of oxygen atoms, and the formation conditions of the RFn type layer, the RFi type layer, the MWi type layer, and the RFp type layer of this example.

Comparative Example 17-1 This example is different from Example 17 in that each semiconductor layer was formed without performing the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms.

Other points were the same as in Example 17. The single film for measuring the interface defect density of this example is (SC ratio 17-1)
I decided to call it.

The above-mentioned two kinds of single films (SC Ex 17) and (SC ratio 17-1) for measuring the interface defect density each have 3
It was made one by one. Table 11 shows PDS (Photothermal Deflect) for each of these single films for measuring the interface defect density.
This is the result of measurement of ion spectroscopy. The results of the measurement are shown by standardizing (SP ex. 17) using (SP ratio 17-1). That is, the numbers in Table 11 indicate the reduction rate of the interface defect density.

[0408]

[Table 11] Here, the PDS measurement method is described in “WB Jackson, D.
K. Biegelsen, JCKnights et. Al. Appl. Phys. Le
tt. 42, 105, (1983) ”, and“ ZE Smith, V. Chu,
TL Chu et. Al. Appl. Phy. Lett. 50, 1521, (198
The method described in 7) was used.

[0409] From Table 11, those subjected to the annealing treatment in the gas atmosphere containing a trace amount of oxygen atoms of the present invention (SP Ex. 1
It was found that the sample No. 7) had a smaller interface defect density and was superior to the sample without the conventional annealing treatment (SP ratio 17-1).

[0410]

[Table 12]

[0411]

[Table 13]

[0412]

[Table 14]

[0413]

[Table 15]

[0414]

[Table 16]

[0415]

[Table 17]

[0416]

[Table 18]

[0417]

[Table 19]

[0418]

[Table 20]

[0419]

[Table 21]

[0420]

[Table 22]

[0421]

[Table 23]

[0422]

[Table 24]

[0423]

[Table 25]

[0424]

[Table 26]

[0425]

[Table 27]

[0426]

[Table 28]

[0427]

[Table 29]

[0428]

[Table 30]

[0429]

[Table 31]

[0430]

[Table 32]

[0431]

[Table 33]

[0432]

[Table 34]

[0433]

[Table 35]

[0434]

[Table 36]

[0435]

[Table 37]

[0436]

[Table 38]

[0437]

[Table 39]

[0438]

[Table 40]

[0439]

[Table 41]

[0440]

[Table 42]

[0441]

[Table 43]

[0442]

[Table 44]

[0443]

[Table 45]

[0444]

[Table 46]

[0445]

[Table 47]

[0446]

[Table 48]

[0447]

[Table 49]

[0448]

[Table 50]

[0449]

[Table 51]

[0450]

【The invention's effect】

(Claim 1) As described above, the invention according to claim 1 provides a method for forming a photovoltaic element, in which impurities adsorbed on or contained in the chamber wall surface are hardly taken into the semiconductor layer. .

(Claim 2) According to the invention of claim 2, there is provided a method for forming a photovoltaic element, which can oxidize the surface of a silicon layer by an appropriate thickness.

(Claim 3) According to the invention of claim 3, a method for forming a photovoltaic element is obtained, which can oxidize the surface of a silicon layer by an appropriate thickness.

(Claim 4) According to the invention of claim 4, there is provided a method of forming a photovoltaic element, which enables high-speed film formation and can form a high-quality film with less photodegradation.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a single photovoltaic element to which a hydrogen plasma treatment method according to the present invention is applied.

FIG. 2 is a schematic cross-sectional view of a tandem photovoltaic element to which the hydrogen plasma processing method according to the present invention is applied.

FIG. 3 is a schematic cross-sectional view of a triple type photovoltaic device to which the hydrogen plasma processing method according to the present invention is applied.

FIG. 4 is a schematic explanatory view of a multi-chamber separation type forming apparatus according to the present invention.

FIG. 5 is a schematic explanatory view of a roll-to-roll type forming apparatus according to the present invention.

FIG. 6 is a schematic explanatory view of a deposition film forming chamber by RF plasma CVD in a roll-to-roll type forming apparatus according to the present invention.

FIG. 7 is a schematic explanatory view of a deposition film forming chamber by microwave plasma CVD in a roll-to-roll type forming apparatus according to 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 antireflection layer), 103, 203, 303 first n-type layer (or p-type layer), 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 collector electrode, 151, 251, 351 first n / i buffer layer, 161, 261, 361 first p / i buffer layer, 190, 290, 390 substrate, 206, 306 second n Mold layer (or p-type layer), 207, 307 second i-type layer, 208, 308 second p-type layer (or n-type layer), 309 third n (or p-type layer), 310 third I-type layer , 311 third p-type layer (or n-type layer), 352 second n / i buffer layer, 362 second p / i buffer layer, 400 multi-chamber separation type deposition device, 401 load lock chamber, 402 n-type layer (or p-type layer) transfer chamber, 403 MW-i or RF-i layer transfer chamber, 404 p-type layer (or n-type layer) transfer chamber, 405 unload chamber, 406-409 gate valve, 410- 412 Heater for heating substrate, 413 Rail for transferring substrate, 417 n-type layer (or p-type layer) deposition chamber, 418 MW-i or RF-i layer deposition chamber, 419 p-type layer (or n-type layer) deposition Chamber, 420, 421 RF introducing cup, 422, 423 RF power source, 424 bias applying power source, 425 MW introducing window, 426 MW introducing waveguide, 427 MW-i deposition shutter 428 bias electrode, 429,449,469 gas supply pipe, 430～434,441～444,450～455,4
61-465, 470-474, 481-484 stop valve, 436-439, 456-460, 476-479 mass flow controller, 490 substrate holder, 5010 load chamber for introducing sheet-like substrate, 5011, 5021, 5031, 5041, 5051,
5061, 5071, 5081, 5091, 5101,
5111, 5121, 5131, 5141, 5151
Exhaust pipe, 5012, 5022, 5032, 5052, 5062,
5072, 5082, 5102, 5112, 5122,
5132, 5142, 5152 exhaust pump, 5020 first n-type layer deposition chamber, 5023, 5033, 5053, 5063, 5073,
5083, 5103, 5113, 5123, 5133,
5143 RF supply coaxial cable, 5024, 5034, 5054, 5064, 5074,
5084, 5104, 5114, 5124, 5134,
5144 RF power supply, 5025, 5035, 5045, 5055, 5065,
5075, 5085, 5095, 5105, 5115,
5125, 5135, 5145 Source gas supply pipe, 5026, 5036, 5046, 5056, 5066,
5076, 5086, 5096, 5106, 5116,
5126, 5136, 5146 Mixing device, 5030 1st RF-i layer (n / i) deposition chamber, 5040 1st MW-i layer deposition chamber, 5042, 5092 Exhaust pump (with diffusion pump), 5043, 5093 MW Introducing waveguide, 5044, 5094 MW power source, 5050 First RF-i layer (p / i) deposition chamber, 5060 First p-type layer deposition chamber, 5070 Second n-type layer deposition chamber, 5080 2 RF-i (n / i) deposition chamber, 5090 2nd MW-i layer deposition chamber, 5100 2nd RF-i layer (p / i) deposition chamber, 5110 2nd p-type layer deposition chamber, 5120 Third n-type layer deposition chamber, 5130 RF-i layer deposition chamber, 5140 Third p-type layer deposition chamber, 5150 Unload chamber, 5201-5214 gas gate, 5301-5314 Gas supply to gas gate Supply tube, 5400 sheet feeding jig, 5401 sheet substrate, 5402 sheet winding jig, 601, 701 deposited film forming chamber, 602 lamp heater, 603, 703 substrate temperature control plate, 604 flat plate or grid electrode , 605 heater, 606, 709 raw material gas introduction pipe, 607 electrode insulating insulator, 608 RF introduction waveguide, 609 exhaust pipe, 610 raw material gas flow, 611, 711 gas gate, 612 gas gate gas supply pipe, 613 gas gate Gap adjusting plate, 614, 615, 713, 714 adjacent deposition chambers, 616, 715 sheet-shaped substrate, 702 substrate heating heater, 704 MW introduction window, 705 bias electrode, 706 mesh-shaped plate, 708 bias applying cable , 710 diffusion pump, 712 gas Gas supply pipe to the over door.

Claims (4)

[Claims] 1. A pin structure formed by stacking n-type, i-type and p-type semiconductor layers containing silicon atoms and having a non-single crystal structure is formed on a substrate at least once. In the method for forming photovoltaic elements arranged repeatedly as described above, at least one surface of the surfaces of the semiconductor layer is
A method for forming a photovoltaic element, which comprises performing an annealing treatment in an atmosphere of hydrogen gas, helium gas, or argon gas containing an oxygen atom-containing gas in an amount of 1 to 1000 ppm. 2. The temperature of the annealing treatment is 50 ° C.
The method for forming a photovoltaic element according to claim 1, wherein the temperature is from about 400 ° C. 3. The pressure of the annealing treatment is 0.0
It is 1 Torr-10 Torr, The formation method of the photovoltaic element of Claim 1 or 2 characterized by the above-mentioned. 4. The photovoltaic element according to claim 1, wherein the microwave used in the microwave plasma CVD method has a frequency of 0.1 to 10 GHz. Forming method.