JPH1187751A - Polycrystalline silicon thin film, photoelectric conversion element, and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polycrystalline silicon thin-film manufacturing method through which a polycrystalline silicon thin film having superior crystallinity can be manufactured at high speed, a photoelectric conversion element manufacturing method through which a photoelectric conversion element can be manufactured with high productivity, and a polycrystalline silicon thin film and a photoelectric conversion element which have less crystalline defects. SOLUTION: In a first process, a polycrystalline silicon thin film is deposited on a base material 5 arranged on a grounding electrode 3 by bringing a hydrogenated silane compound, introduced to a reaction chamber 1 into contact with the base material 5 after plasma has been generated from the compound between each electrode, while a high frequency is impressed upon an electrode 2 for impressing high frequency. In a second process, another polycrystalline silicon film is deposited additionally on the polycrystalline silicon base layer formed on the base material 5 in the first process, by bringing a chlorinated silane compound, which is supplied to the container 1 and from which plasma is generated, into contact with the polycrystalline silicon base layer formed on the base material 5 in the first process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a polycrystalline silicon thin film used as a solar cell, a method for manufacturing a photoelectric conversion element, and a polycrystalline silicon thin film and a photoelectric conversion element.

[0002]

2. Description of the Related Art As a silicon-based thin-film solar cell, an amorphous-silicon thin-film solar cell using amorphous silicon for a photoelectric conversion layer is widely known. It has already been put to practical use as a consumer power supply. However, the performance and reliability of the current amorphous silicon thin-film solar cell cannot be said to be sufficient for high-power applications in place of fossil fuels, and further improvements in performance are required.
The reason is that energy conversion efficiency is lower than that of a crystalline silicon solar cell using a single crystal silicon wafer or the like, and that a so-called light degradation phenomenon in which the energy conversion efficiency gradually decreases with the power generation time is observed. .

For the purpose of improving the performance and reliability of such silicon-based thin-film solar cells, attempts have recently been made to change the photoelectric conversion material from an amorphous silicon thin film to a polycrystalline silicon thin film. The reason is that the above-mentioned photodegradation phenomenon is not observed in a solar cell using a polycrystalline silicon thin film, and it is considered that a highly reliable solar cell can be obtained. Further, the polycrystalline silicon thin-film solar cell has a feature in terms of performance that absorption efficiency of long-wavelength light is higher than that of an amorphous silicon solar cell. Therefore, when the amorphous silicon thin film solar cell and the polycrystalline silicon thin film solar cell are stacked, the difference in the light absorption characteristics between the amorphous silicon thin film and the polycrystalline silicon thin film can be effectively used, and It is possible to manufacture a silicon-based thin-film solar cell having high conversion efficiency and excellent reliability.

As an example of actually applying a polycrystalline silicon thin film to a photoelectric conversion layer of a solar cell, Materials Research Society Symposium Proceeding, No. 4
Volume 20, pages 3-14 Published in 1996 (On The Way Towards
High Efficiency Thin FilmSilicon Solar cells By T
he Micromorph Concept, Mateial Research SocietySym
posium Proceeding (vol.420, p.3-14 (1996)))
A trial example of a stacked solar cell in which an amorphous silicon solar cell and a polycrystalline silicon solar cell are stacked has been reported. According to the report, the conversion efficiency of the polycrystalline silicon thin film solar cell is 7.7%, and the conversion efficiency of the stacked solar cell is 13.
It is 1%, which confirms that the conversion efficiency is improved by laminating with an amorphous silicon solar cell, and also describes that a polycrystalline silicon thin film solar cell is unlikely to cause a photodegradation phenomenon.

[0005]

As a technique for producing a polycrystalline silicon thin film used as a material for a polycrystalline silicon thin film solar cell, chemical vapor deposition (hereinafter referred to as CVD) is known.
The method is generally used, and among them, the high frequency plasma CVD method is preferably used.

As a specific method for producing such a polycrystalline silicon thin film, Japanese Unexamined Patent Publication No. Hei 5-90158 discloses a method of supplying a silicon-based thin film forming material in an atmosphere containing charged particles obtained from a specific gas. A method of manufacturing a polycrystalline silicon thin film by repeatedly performing the stop is disclosed. According to the description of Japanese Patent Application Laid-Open No. 5-90158, this manufacturing method is effective when the film thickness obtained in one repetition step is 1 to 100 Å.

According to the method of manufacturing a polycrystalline silicon thin film described in Japanese Patent Application Laid-Open No. 5-90158,
A polycrystalline silicon thin film having excellent crystallinity can be obtained even if the thickness is as thin as 0 Å or less. According to this method, the deposition rate of the polycrystalline silicon thin film is about 1 angstrom per second, and a manufacturing process in which the film forming step and the modifying step are repeated is required.

On the other hand, according to Japanese Patent Publication No. 4-137725, SiF ₄ ,
It is shown that a polycrystalline silicon thin film can be obtained by performing a plasma CVD method under the condition that at least one of Si ₂ F ₆ and SiCl ₄ is mixed with a hydrogen atom supply gas at an appropriate ratio. The polycrystalline silicon thin film manufactured by this disclosed technique is crystallographically (10
It is strongly oriented in the 0) direction, and growth of crystal grains of up to 5 microns has been confirmed. According to the disclosed technique, the deposition rate of the polycrystalline silicon thin film is about 0.3 angstroms per second.

The above-mentioned Material Research Society Symposium Proceeding, No. 420
Volume 3-14, published in 1996 (vol.420, p.3-14 (1996))
Describes an example in which a polycrystalline silicon thin film is deposited from a mixed gas of SiH ₄ and H ₂ by a very high frequency (VHF) CVD method.

However, in any of the conventional examples described above, when a thick film of at least about 3 microns required for a photoelectric conversion layer of a polycrystalline silicon thin-film solar cell is obtained, a large amount of manufacturing time is required, and There is a problem that it is not a practical method in general production. Further, the photoelectric conversion efficiency of the polycrystalline silicon thin film solar cell has been required to be further improved.

In view of the above problems in the prior art, the present invention provides a method of manufacturing a polycrystalline silicon thin film capable of manufacturing a polycrystalline silicon thin film having excellent crystallinity and electrical characteristics at a high speed, and a silicon-based thin film solar cell. A method for manufacturing a photoelectric conversion element capable of improving the performance and reliability of a battery, a method for manufacturing a polycrystalline silicon thin film and a method for manufacturing a photoelectric conversion element, which have high performance and reliability with few crystal defects It is an object of the present invention to provide a polycrystalline silicon thin film and a photoelectric conversion element having a high density.

[0012]

Means for Solving the Problems The present inventors have intensively studied to solve the above problems. As a result, the present inventors have found a technique for producing a polycrystalline silicon thin film at a higher speed than the conventional technique and without generating dust such as powder and flakes as a source of crystal defects in plasma during the production process. In addition, it was confirmed that the obtained polycrystalline silicon thin film exhibited extremely excellent crystallinity and electrical characteristics, and based on such knowledge, the present invention was completed.

[0013] The first invention of the present application for solving the above problems is as follows.
A first step of forming a polycrystalline silicon base layer on the substrate by converting the hydrogenated silane gas into a plasma and contacting the base material with the base material; And a second step of depositing a crystalline silicon thin film.

According to the method for producing a polycrystalline silicon thin film of the first invention of the present application, in the first step, the polycrystalline silicon base layer formed on the base material with good crystallinity is formed with crystal nuclei. Therefore, a polycrystalline silicon film can be formed at a high speed in the second step.

By controlling the thickness of the polycrystalline silicon base layer deposited in the first step to about 10 to 150 angstroms, the polycrystalline silicon base layer having good crystallinity can be formed on the substrate. A polycrystalline silicon film can be formed at a high speed in the second step using the crystalline silicon base layer as a crystal nucleus. Here, the gas containing at least the halogenated silane in the first invention of the present application can be a mixed gas of a hydrogenated silane and a halogenated silane.

The second invention of the present application is a method for manufacturing a photoelectric conversion element in which a p-layer (or n-layer), an i-layer and an n-layer (or p-layer) are laminated on a substrate in this order. A method of manufacturing a photoelectric conversion element, comprising the following steps (1) to (3). (1) A mixed gas of hydrogenated silane and a Group III element compound of the Periodic Table (or a Group V element compound of the Periodic Table) is converted into a plasma and brought into contact with the substrate to form a plasma on the substrate. A step of forming a p-layer (or n-layer) having a thickness of about 10 to 150 angstroms by depositing polycrystalline silicon containing a group V element (or a group V element of the periodic table) (2) including at least a halogenated silane The gas is turned into a plasma and brought into contact with the p-layer (or n-layer) to form p-type gas.
Step of depositing polycrystalline silicon on layer (or n-layer) to form i-layer (3) At least one of hydrogenated silane or halogenated silane and Group V element compound of periodic table (or periodicity) The mixed gas of the group III element in the periodic table is turned into plasma and brought into contact with the i-layer formed in the step (2) to form a group V element in the periodic table (or group III in the periodic table) on the i-layer.
Forming an n-layer (or p-layer) by depositing polycrystalline silicon containing a group element).

According to the second invention of the present application, a p-layer (or an n-layer) in which polycrystalline silicon is doped with a Group III element of the periodic table (or a Group V element of the periodic table), and
Intrinsic semiconductor layer (i-layer) laminated on layer (or n-layer)
And an n-layer (or p-layer) in which polycrystalline silicon laminated on the i-layer is doped with a Group V element of the periodic table (or a Group III element of the periodic table). It can be produced with high efficiency adapting to the industrial production process at speed. The gas containing at least the halogenated silane in the step (2) of the second invention of the present application can be a mixed gas of hydrogenated silane and halogenated silane.

Further, the third invention of the present application is directed to a polycrystalline silicon base layer formed on a substrate by converting a hydrogenated silane gas into a plasma and bringing the same into contact with the base material, and forming at least a halogenated halogen on the polycrystalline silicon base layer. A polycrystalline silicon thin film composed of a polycrystalline silicon thin film main layer formed by plasma-forming a gas containing silane and having a crystal volume fraction of about 85% or more and a dark conductivity of about 1 × 10 ^−3. The above is the polycrystalline silicon thin film. Such a polycrystalline silicon thin film of the third invention of the present application has extremely few crystal defects caused by dust such as powder and flakes generated in plasma during the manufacturing process, and exhibits extremely excellent crystallinity and electric characteristics.

The fourth invention of the present application is also directed to a method in which a mixed gas of hydrogenated silane and a Group III element compound of the periodic table (or a Group V element compound of the periodic table) is plasmatized and brought into contact with a substrate. A p-layer (or n-layer) having a thickness of about 10 to 150 angstroms obtained by depositing polycrystalline silicon containing a group III element of the periodic table (or a group V element of the periodic table) on a substrate; A gas containing at least a halogenated silane is turned into plasma, and the i-layer formed by contacting the p-layer (or the n-layer) with at least one of hydrogenated silane or halogenated silane, and V in the periodic table. A mixed gas of a Group III element compound (or a Group III element in the Periodic Table) is turned into a plasma and brought into contact with the i-layer to form a Group V element in the Periodic Table (or a Group III element in the Periodic Table) on the i-layer. Deposited polycrystalline silicon containing A photoelectric conversion element comprising an n-layer (or p-layer) formed by
m, wherein the quantum efficiency at m is 0.7 or more, and the ratio of the conversion efficiency after 20,000 spectral irradiation to the initial conversion efficiency is about 0.95 or more. The photoelectric conversion element according to the fourth invention of the present application has extremely few crystal defects caused by dust such as powder and flakes generated in plasma during the manufacturing process, has extremely excellent crystallinity and electric characteristics, and has high performance. Thus, a highly reliable silicon-based thin-film solar cell can be manufactured.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

A. The method of manufacturing the polycrystalline silicon thin film of the first invention of the present application The deposition of the polycrystalline silicon thin film in the method of manufacturing the polycrystalline silicon thin film of the first invention of the present application includes the first step for forming a crystal nucleus and the crystal growth. For the second step. More specifically, the hydrogenated silane gas heated in the first step is turned into plasma and brought into contact with the substrate to form a crystal nucleus of polycrystalline silicon, that is, a base layer on the substrate. Thereafter, in a second step, a gas containing at least a halogenated silane is converted into plasma to deposit a polycrystalline silicon thin film having excellent crystallinity and electrical characteristics on the base layer at a high speed.

(1) Thickness of Base Layer Deposited in First Step The thickness of the polycrystalline silicon base layer formed in the first step is as follows:
In the present invention, it is essential that the crystallinity of the polycrystalline silicon thin film deposited in the second step be equal to or more than the specified minimum thickness due to the crystallinity of the polycrystalline silicon base layer. Thereby, it is compensated that the polycrystalline silicon base layer having good crystallinity formed in the first step maintains good crystallinity of the polycrystalline silicon thin film formed in the second step,
A polycrystalline silicon thin film having high electrical characteristics such as photoconductivity as well as high-speed film formation can be formed. If the thickness of the base layer is less than the thickness at which the crystallinity of the polycrystalline silicon thin film deposited in the second step is defined, the crystal of the polycrystalline silicon thin film deposited on the base layer at a high speed in the second step The properties are disturbed, and the electrical characteristics such as the photoconductivity of the polycrystalline silicon thin film finally obtained are deteriorated.

From this viewpoint, if the thickness of the base layer deposited in the first step is more specifically defined, it is preferable that the thickness of the base layer is about 10 Å to 150 Å. It is more preferable that the thickness of the base layer be 20 Å or more and 100 Å or less in order to further exert the effects of the present invention. If the thickness of the base layer is less than about 10 angstroms, the crystallinity of the polycrystalline silicon thin film deposited on the base layer at a high speed is disturbed, and the electrical characteristics such as the photoconductivity of the polycrystalline silicon thin film are deteriorated. When the thickness of the base layer exceeds 150 angstroms, deterioration of the structure such as the crystallinity or the electrical characteristics such as the photoconductivity is not observed, but a great amount of time is required for deposition. It does not fulfill the technical problem to be solved.

(2) Substrate Surface Temperature in the First Step In the first step of the present invention, when the hydrogenated silane gas is converted into plasma and brought into contact with the substrate, the substrate is heated to form a film. A polycrystalline silicon thin film that activates a surface reaction during formation, improves the crystallinity of the base layer obtained in the first step, improves film formation efficiency, and deposits on the base layer at a high rate in the second step By improving the crystallinity of the polycrystalline silicon thin film, the film formation efficiency of the finally obtained polycrystalline silicon thin film can be improved, and electrical characteristics such as photoconductivity can be improved. More specifically, the substrate surface temperature in the first step is preferably set to a temperature of 100 ° C or higher and 350 ° C or lower, more preferably 150 ° C or higher and 300 ° C or lower. When the substrate surface temperature is lower than 100 ° C., the crystallinity of the base layer obtained in the first step is deteriorated, and the electric characteristics such as photoconductivity are deteriorated. The substrate temperature is 350 ° C
Even in a higher case, the crystallinity of the base layer obtained in the first step is deteriorated, and electrical characteristics such as photoconductivity are reduced.

(3) Base layer surface temperature in the second step In the first invention of the present application, the halogenated silane gas plasmatized in the second step is brought into contact with the polycrystalline silicon base layer formed in the first step to form the second layer. In depositing the polycrystalline silicon on the polycrystalline silicon base layer formed in one step, it is preferable to heat the polycrystalline silicon base layer formed in the first step. This makes it possible to deposit the polycrystalline silicon thin film on the base layer at a high speed in the second step, and also to improve the crystallinity of the obtained polycrystalline silicon thin film, and to improve the light of the finally obtained polycrystalline silicon thin film. Electrical characteristics such as conductivity can be improved.

From this viewpoint, the surface temperature of the base layer in the second step is 200 ° C. or more and 600 ° C. or less, more preferably 250 ° C. or more and 400 ° C. or less, and the temperature difference from the substrate heating temperature in the first step is 30 ° C. It is important to set a temperature range that is higher than or equal to ° C and lower than or equal to 450 ° C. When the surface temperature of the base layer in the second step is lower than 200 ° C., the crystallinity is reduced and the electrical properties such as photoconductivity are deteriorated.
The effect of the present invention cannot be sufficiently exhibited. 600
If the temperature exceeds ℃, the raw material gas is thermally decomposed in the vicinity of the base layer surface, and as a result, a decrease in crystallinity is observed. When the temperature difference between the base layer surface temperature in the second step and the substrate heating temperature in the first step is not 30 ° C. or more, the reaction on the base layer surface is not efficiently performed, and polycrystalline silicon is deposited at a high speed. I can't. Also,
When the temperature difference is 450 ° C. or more, the crystallinity is disturbed and the electrical properties are reduced.

(4) Raw Material for Polycrystalline Silicon Thin Film Used as Base Layer In the present invention, the silane hydride used as a raw material for the polycrystalline silicon thin film used as the base layer is represented by the general formula Si _n H
_{(2n + 2)} (however, n is a natural number of 1 or more), and is not particularly limited as long as it can be gasified. Examples of hydrogenated silanes that can be suitably used include SiH ₄ (monosilane), Si ₂ H ₆ (disilane),
Si ₃ H ₈ (trisilane) and the like. In the first step, the hydrogenated silane may be used as a mixture with a gas of another silane compound such as a halogenated silane. % Is required. If the ratio of the hydrogenated silane is less than 50 mol%, the structure of the obtained thin film is not polycrystalline but an amorphous structure, and after the second step, the structure is still amorphous and the effect of the present invention is obtained. Cannot be obtained.

(5) Temperature Range for Preheating the Hydrogenated Silane Gas Further, in the present invention, by preheating the hydrogenated silane gas in the first step, heat energy is supplied to the hydrogenated silane molecules and adhered to the substrate. Later, a more stable structure can be built. In that case,
It is preferable that the temperature range in which the hydrogenated silane gas is preliminarily heated is 400 ° C. or more and 600 ° C. or less. More preferably, the temperature is 450 ° C. or more and 550 ° C. or less. By previously heating the hydrogenated silane gas to the above temperature range, thermal energy is efficiently supplied to the hydrogenated silane molecules, a more stable structure is formed after the deposition on the substrate, and a polycrystalline silicon base layer having good crystallinity is formed. This is because it can be formed. In the second step, by preheating a gas containing at least a halogenated silane, the efficiency of film formation can be improved and the productivity can be increased. However, from the viewpoint of the crystallinity of the obtained polycrystalline silicon thin film, preheating of at least the gas containing the halogenated silane is not essential,
The gas temperature may be in the range of 15 (about room temperature) to 550 ° C. This is because a polycrystalline silicon base layer having good crystallinity has already been formed in the first step, and it is not particularly necessary to preheat the gas.

The silane gas can be supplied in a mixture with a non-deposition gas such as hydrogen, helium, argon, and xenon which does not participate in the deposition of the polycrystalline silicon thin film. When hydrogen is used among the above-mentioned diluent gases, the effect of the present invention is remarkably exhibited. More specifically, a good crystal nucleus is formed when hydrogen is supplied at about 5 to 100 times the flow rate of monosilane in a standard state. Although detailed research has been done on this reason, no clear reason is currently given.

(6) Raw Material for Polycrystalline Silicon Thin Film in Second Step The halogenated silane used as the raw material for the polycrystalline silicon thin film in the second step can be gasified having at least one halogen atom in the molecule. There is no particular limitation as long as it is a silane compound. Suitable halogenated _{silane, SiH m X (4- m)} ( where, m is an integer of 0 to 3,
X is a fluorine atom, a chlorine atom or a bromine atom. )). Specific examples of such halogenated silanes include SiF ₄ (tetrafluorosilane), SiF ₃ H (trifluorofluorosilane), and SiF ₂ H
₂ (Jifuroroshiran), SiFH ₃ (mono fluoroalkyl silane), SiCl ₄ (tetrachlorosilane), SiCl ₃ H
(Trichlorosilane), SiCl ₂ H ₂ (dichlorosilane), SiClH ₃ (monochlorosilane) and the like.

In the second step, it is important to use such a halogenated silane in order to rapidly deposit a polycrystalline silicon film having excellent crystallinity and high photoconductivity. In the second step, a gas containing at least such a halogenated silane may be used in the form of a plasma, and the halogenated silane may be used as a mixture with another silane compound gas such as the above-mentioned hydrogenated silane. Can also. At this time, from the viewpoint of the properties of the obtained polycrystalline silicon thin film, it is preferable that the ratio of the halogenated silane to all the silanes converted into plasma is 50 mol% or more. In particular, when used in combination with the above-mentioned hydrogenated silane, a polycrystalline silicon thin film having excellent crystallinity and high photoconductivity can be deposited at a higher speed.

Since halogenated silane is used as a raw material in the second step, a halogen atom can be contained in the polycrystalline silicon film formed in this step. Thus, the light transmittance of the polycrystalline silicon thin film can be increased. For example, in a polycrystalline silicon thin film solar cell, conversion efficiency is expected to be increased by forming a part of the p-layer into a polycrystalline silicon thin film having a high light transmittance as obtained in this step. The amount of halogen atoms in the polycrystalline silicon thin film formed in this step is about 0.00
Although the content can be controlled to 5 to 5 atomic%, a preferable halogen atom content is about 0.01 to 3 atomic%, particularly preferably about 0.1 to 1 atomic% from the viewpoint of transmittance. Further, the halogen atom is preferably a chlorine atom.

The above silane gas may be supplied alone,
It is also possible to supply by diluting with a non-deposition gas such as helium, argon, and xenon which does not participate in the deposition of the polycrystalline silicon thin film. When hydrogen is used among these dilution gases, the effect of the present invention is remarkably exhibited.

(7) Reaction pressure at the time of depositing a polycrystalline silicon thin film In the present invention, the reaction pressure at the time of depositing a polycrystalline silicon thin film is 1 mTorr or more and 500 mTorr or less in the first step, and 5 mT
It is preferable that the pressure is not less than orr and not more than 1000 mTorr. Further, a preferable result can be obtained by setting the reaction pressure in the second step higher than the reaction pressure in the first step by 3 to 800 mTorr.

If the reaction pressure in the first step is less than 1 mTorr, stable plasma cannot be formed, which is a problem in production. On the other hand, when the pressure exceeds 500 mTorr, the raw material gas is agglomerated, so that powder is generated in the plasma, which causes point defects in the film and lowers the production yield.

If the reaction pressure in the second step is less than 5 mTorr, the effect of the present invention cannot be exhibited because the deposition rate of the polycrystalline silicon thin film decreases. Also, 100
If the pressure exceeds 0 mTorr, it becomes difficult to stably form plasma, which is a problem in manufacturing.

If the reaction pressure in the second step is not higher than the reaction pressure in the first step by 3 mTorr or more, it is difficult to increase the deposition rate of the polycrystalline silicon thin film. Also, the reaction pressure in the second step is 800 mTorr lower than the reaction pressure in the first step.
If it exceeds r, crystallinity tends to be disordered.

(8) Method for Heating the Source Gas In the first step and, if necessary, the second step, the method for heating the source gas may be any known means without particular limitation. That is, a method in which a gas pipe is directly heated by a heater, a method in which a gas pipe is heated by high-frequency induction heating, and a preliminary chamber provided with a gas heater in advance,
A method of preheating with an infrared lamp or the like is suitably employed without any particular limitation.

(9) Measurement and adjustment of temperature The temperature of the hydrogenated silane gas to be heated in advance in the first step is difficult to measure accurately, so that at present, the temperature of the gas pipe is used as the gas temperature. The length is set to be long enough to make the temperature uniform. In addition, when heating the hydrogenated silane gas by a heater (for example, 6a in FIG. 1) in the reaction vessel, the present inventors consider the physical properties of the obtained polycrystalline silicon film and the hydrogenated silane gas heated as described above. It has been confirmed that the set temperature of the heater can be used as the gas temperature based on the correlation with the heating temperature of the silane gas. The gas temperature in the case where the gas is heated in the second step can be adjusted in the same manner.

(10) Management of Utilization Rate In the present invention, the first step and the second step are defined as the amount of polycrystalline silicon formed in each step with respect to the total supply amount of all silanes used in each step. By controlling the “utilization rate” defined by the above, a polycrystalline silicon thin film having extremely few defects can be efficiently manufactured. Here, the utilization rate is calculated by the following equation.

[0040]

(Equation 1)

In the above formula, the total silane used in each step means all silanes serving as a source of Si atoms. In the second step, all other silanes such as hydrogenated silanes which can be used in combination with the halogenated silanes are contained in the second step. In the above formula, the "total supply amount of all silanes" and the "amount of polycrystalline silicon formed in each step" are both expressed on the basis of Si atoms (the number of Si atoms).

When the utilization is low, the production efficiency of the polycrystalline silicon thin film is reduced, while when the utilization is excessive, decomposition products which adversely affect the deposition of the film are generated. This adheres to the base material or the base layer and becomes a physical defect, deteriorating the crystallinity. The preferred range of utilization depends on the composition of the silane gas used and the purpose of utilization control. The purpose of the utilization control in the present invention is as follows. A polycrystalline silicon base layer serving as a seed crystal is formed. A polycrystalline silicon substrate is grown. A polycrystalline silicon thin film is deposited at high speed on a polycrystalline silicon base layer.

In order to efficiently obtain a polycrystalline silicon thin film having good crystallinity, the utilization in the first step and the second step should be about 0.5 to 10% and about 10 to 80%, respectively.
, Particularly preferably about 1 to 5% and about 30 to respectively.
It is better to manage within the 60% range. The above utilization rate is based on the supply rate or temperature of the silane used in each step, the supply rate or temperature when using a diluent gas, the temperature of the base material or the polycrystalline silicon base layer, the pressure in the reactor, or the generation of plasma. Can be controlled by one or more of the amount of energy added to the fuel cell.

(11) Substrate Used in the Present Invention The substrate used in the present invention is not particularly limited, and may be appropriately selected depending on the solar cell forming process and application. For example, when used as a photoelectric conversion layer of a solar cell, as a substrate, quartz glass, blue plate glass, single crystal silicon, polycrystalline silicon,
Various metals, heat-resistant polymers, transparent conductors and the like can be used.

(12) Other manufacturing conditions of the polycrystalline silicon thin film In the present invention, the deposition of the polycrystalline silicon thin film is not particularly limited as long as the above manufacturing conditions are satisfied. Adopted without. For example, as a means for converting the raw material gas into plasma in the first step and the second step, a known method such as a high frequency, an ultrashort wave, a low frequency, or a microwave is used without any particular limitation.

(13) Apparatus for carrying out the present invention The apparatus for carrying out the present invention is not particularly limited. An example of a typical device is the device shown in FIG. That is, a set of parallel plate electrodes 2 and 3 is arranged inside the reaction vessel 1. A high frequency generator 4 is connected to the high frequency application electrode 2, and a high frequency is applied from the high frequency generator 4 to the high frequency application electrode 2. Further, a base material 5 is set on the ground electrode 3. Heaters 6a and 6b are embedded in the high-frequency application electrode 2 and the ground electrode 3, respectively, and the gas temperature can be adjusted by the heater 6a and the substrate temperature can be adjusted by the heater 6b.

Further, gas pipes 7a and 7b are connected to positions where gas such as hydrogen, a hydrogenated silane compound and a halogenated silane compound can be supplied to the reaction vessel 1. When the hydrogenated silane compound is preliminarily heated in the first step of the method for producing a polycrystalline silicon thin film of the present invention, the heater 6 embedded in the high-frequency application electrode 2 is used.
a or heater 10 attached to gas pipe 7b
, The gas can be heated to a predetermined temperature.

Further, a vacuum pump 8
Is attached, and the inside of the reaction vessel 1 can be evacuated by the vacuum pump 8. In addition, a pressure regulator 9 is attached so that the vacuum pump 8 can be controlled, and the pressure regulator 9 can keep the inside of the reaction vessel 1 at a constant pressure. Flow controllers 11a and 11b are attached to the gas pipes 7a and 7b, respectively.
The flow rates of the gas from the gas pipes 7a and 7b can be controlled by using a and 11b.

A shutter 12 is arranged between the high frequency application electrode 2 and the ground electrode 3. The shutter 12 is arranged so as to be openable and closable between the high frequency application electrode 2 and the ground electrode 3. When the shutter 12 is closed during plasma generation, plasma is generated only between the shutter 12 and the high frequency application electrode 2. However, no polycrystalline silicon film is deposited on the substrate 5.

Next, a method for producing a polycrystalline silicon thin film of the present invention using the above-described apparatus for producing a polycrystalline silicon thin film will be described. First, in the first step, the flow rates of hydrogen and the hydrogenated silane compound are controlled by the flow rate controllers 11a and 11b, and then supplied to the reaction vessel 1 from the gas pipes 7a and 7b. At this time, the hydrogenated silane compound is applied to the electrode 2 for high frequency application.
Heated in advance by a heater 6a embedded therein or a heater 10 attached to a gas pipe 7b. Then, a high frequency is applied from the high frequency generator 4 to the high frequency application electrode 2, and the gas introduced into the reaction vessel 1 is turned into plasma between the electrodes. The plasma gas is brought into contact with the substrate 5 disposed on the ground electrode 3 heated to a certain temperature by the heater 6b, whereby a thin polycrystalline silicon thin film is deposited on the substrate 5.

Subsequently, in the second step, the gas pipe 7
a, the supply of the hydrogenated silane compound from 7b is stopped,
The flow rate of the halogenated silane compound is controlled by gas flow controllers 7a and 11b from gas pipes 7a and 7b, and the reaction vessel 1
Supplied inside. Then, similarly to the first step, a high frequency is applied from the high frequency generator 4 to the high frequency application electrode 2,
The gas introduced into the reaction vessel 1 is heated by the heater 6a as required, and is turned into plasma between the electrodes. The plasma gas is heated to a certain temperature by a heater 6b embedded in the ground electrode 3, and comes into contact with the thin polycrystalline silicon base layer formed on the base material 5 in the first step, and the thin polycrystalline silicon A polycrystalline silicon film is further deposited on the base layer.

B. The manufacturing method of the photoelectric conversion element of the second invention of the present application The manufacturing method of the photoelectric conversion element of the second invention of the present application is configured by applying the method of manufacturing the polycrystalline silicon thin film of the first invention of the present application. Therefore, the conditions applied to the method for manufacturing a polycrystalline silicon thin film according to the first invention of the present application are similarly applied to the method for manufacturing a photoelectric conversion element according to the second invention of the present application. This will be specifically described below.

The deposition of the polycrystalline silicon thin film in the method of manufacturing a photoelectric conversion element according to the second invention of the present application differs from the method of depositing a polycrystalline silicon thin film in the method of manufacturing a polycrystalline silicon thin film of the first invention of the present application. Similarly, a step (1) of forming a crystal nucleus and using it as a p-layer (or n-layer), a step (2) of growing a crystal to obtain an i-layer, and further, an n-layer (or p-layer) on the i-layer The step (3) of forming the layer (3) is performed. Specifically, in the step (1), the hydrogenated silane gas heated is converted into plasma and brought into contact with the substrate to form a crystal nucleus of polycrystalline silicon, that is, a base layer on the substrate, which is formed into a p-layer (or n-layer). And Then, in step (2), a gas containing at least a halogenated silane is converted into plasma, and an i-layer made of a polycrystalline silicon thin film having excellent crystallinity and electrical properties is deposited on the p-layer at a high speed. An n-layer (or p-layer) is formed on the i-layer.

(1) Overall process of the method for manufacturing a photoelectric conversion element according to the second invention of the present application In the method for manufacturing a photoelectric conversion element according to the second invention of the present application, in step (1), hydrogenated silane and the periodic table are used. A mixed gas with a Group III element compound (or a Group V element compound in the periodic table) is turned into a plasma and brought into contact with the substrate to form a Group III element (or a Group V element in the Periodic Table) on the substrate. Element) is deposited to form a p-layer (or n-layer), and in step (2), a gas containing halogenated silane is turned into plasma and brought into contact with the p-layer (or n-layer). depositing polycrystalline silicon on the p-layer (or n-layer)
A layer is formed, and in the step (3), a mixed gas of at least one of a silane of hydrogenated silane and a halogenated silane and a group V element compound of the periodic table (or a group III element compound of the periodic table) is used. Plasma is formed, and polycrystalline silicon containing a group V element of the periodic table (or a group III element of the periodic table) is deposited on the i-layer formed in step (2) to form an n-layer (or p-layer).
Layer). Thereby, i-layer, n-layer (or p-layer)
Can be formed at a high speed with a gas containing a halogenated silane, and the film formation efficiency can be improved. In this case, it is not always necessary to use a halogenated silane in the step (3). This is because the thickness of the n-layer (or p-layer) formed in the step (3) is small, and the demand for high-speed film formation using a gas containing halogenated silane is not large.

In the step (1) for forming the p-layer (or n-layer), a mixed gas of hydrogenated silane and a Group III element compound of the periodic table (or a Group V element compound of the periodic table) is subjected to plasma treatment. To form p-layer 1 (or n-layer 1) by depositing polycrystalline silicon containing a Group III element of the periodic table (or a Group V element of the periodic table) on the substrate by contact with the substrate. And
Next, a mixed gas of at least one of a silane of hydrogenated silane and a halogenated silane and a group III element compound of the periodic table (or a group V element compound of the periodic table) is plasmatized, and the p layer 1 (or the n layer 1) is formed. ) To deposit polycrystalline silicon containing a Group III element of the periodic table (or a Group V element of the periodic table) on the p layer 1 (or the n layer 1), thereby forming a p layer 2 (or an n layer). 2), and the thickness of the p layer 1 (or n layer 1) and the p layer 2 (or n layer 2) is about 10 to 10
A step of forming a 150-angstrom p-layer (or n-layer) may be performed, and then the step (2) may be performed.

By doing so, in step (1), p
Step (1) compared to forming the entire layer (or n-layer)
After the p-layer 1 (or n-layer 1) is formed, the p-layer 2 (or n-layer 2) and the i-layer can be formed at a high speed with a gas containing a halogenated silane, thereby further improving the film formation efficiency. Can be done.

(2) Thickness of p-layer (or n-layer) formed in step (1) The thickness of the p-layer (or n-layer) formed in step (1) depends on the thickness of the p-layer (or n-layer). It is essential in the method for manufacturing a photoelectric conversion element according to the second invention of the present application that the thickness of the polycrystalline silicon thin film deposited in the step (2) by the crystallinity of the polycrystalline silicon thin film be equal to or more than the specified minimum thickness. As a result, the p formed of the polycrystalline silicon thin film having good crystallinity formed in the step (1) is formed.
The layer (or the n-layer) compensates for the good maintenance of the crystallinity of the i-layer, ie, the polycrystalline silicon thin film formed in the step (2). A photoelectric conversion element having good electric characteristics is formed. p
When the thickness of the layer (or the n-layer) is less than the thickness at which the crystallinity of the i-layer deposited in the step (2), that is, the polycrystalline silicon thin film is defined, the p-layer (or the n-layer) in the step (2) ), The crystallinity of the i-layer, that is, the polycrystalline silicon thin film deposited at a high speed is disturbed, and the electrical characteristics such as the photoconductivity of the finally obtained photoelectric conversion element deteriorate.

From this viewpoint, if the thickness of the p-layer (or n-layer) deposited in the step (1) is more specifically defined,
The thickness of the layer (or n-layer) is about 10 angstroms or more and 1
It is preferable that the thickness be 50 Å or less. The thickness of the p-layer (or n-layer) is 20 Å or more and 100
It is more preferable that the thickness be equal to or less than angstrom in order to further exert the effects of the present invention. If the thickness of the p-layer (or n-layer) is less than about 10 angstroms, the crystallinity of the i-layer or polycrystalline silicon thin film deposited at a high rate on the p-layer (or n-layer) will be disturbed, and the ultimately obtained The electrical characteristics such as the photoconductivity of the resulting photoelectric conversion element deteriorate. When the thickness of the p-layer (or the n-layer) exceeds 150 angstroms, deterioration of the structure such as the crystallinity or the electrical properties such as the photoconductivity is not observed, but a great amount of time is required for deposition. Therefore, the present invention does not satisfy the technical problem to be solved by the present invention.

(3) Substrate Surface Temperature in Step (1) In the step (1) of the method for producing a photoelectric conversion element according to the second invention of the present application, when the hydrogenated silane gas is converted into plasma and brought into contact with the substrate, By heating the substrate, the surface reaction at the time of film formation is activated and the step (1) is performed.
The crystallinity of the p-layer (or n-layer) obtained by the method described above is improved and the film formation efficiency is improved.
To improve the crystallinity of the i-layer, i.e., the polycrystalline silicon thin film, deposited at a high speed on the layer, to improve the manufacturing efficiency of the finally obtained photoelectric conversion element and to improve the electrical conductivity such as photoconductivity. The characteristics can be improved. More specifically, the substrate surface temperature in the step (1) is preferably set to a temperature of 100 ° C. or more and 350 ° C. or less, preferably 150 ° C. or more and 300 ° C. or less. Substrate surface temperature is 100
If the temperature is lower than ℃, the crystallinity of the p-layer (or n-layer) obtained in the step (1) is deteriorated, and the electrical properties such as photoconductivity are deteriorated. Further, even when the substrate temperature is higher than 350 ° C., the crystallinity of the p-layer (or n-layer) obtained in the step (1) is deteriorated, and the electrical properties such as photoconductivity are reduced.

(4) The p-layer (or n-layer) in step (2)
Layer) Surface temperature In the method for manufacturing a photoelectric conversion element of the second invention of the present application,
Contacting the p-layer (or n-layer) formed in step (1) with the halogenated silane gas plasmaized in step (2) to form polycrystalline silicon on the p-layer (or n-layer) formed in step (1) In depositing, the p-layer (or n-layer) formed in step (1) is preferably heated. This makes it possible to deposit an i-layer, that is, a polycrystalline silicon thin film at a high rate on the p-layer (or n-layer) in step (2), and to improve the crystallinity of the resulting i-layer, that is, the polycrystalline silicon thin film. In addition, the electrical characteristics such as the photoconductivity of the finally obtained photoelectric conversion element can be improved.

From this viewpoint, the surface temperature of the p-layer (or n-layer) in the step (2) is 200 ° C. or more and 600 ° C. or less, more preferably 250 ° C. or more and 400 ° C. or less. It is important to set a temperature range in which the temperature difference from the temperature is higher than 30 ° C. and lower than 450 ° C. When the surface temperature of the p-layer (or n-layer) in step (2) is lower than 200 ° C., the crystallinity is reduced and the electrical properties such as photoconductivity are deteriorated, so that the effects of the present invention can be sufficiently exhibited. Can not. When the temperature exceeds 600 ° C., the raw material gas is thermally decomposed in the vicinity of the p-layer (or n-layer) surface, and as a result, a decrease in crystallinity is observed. If the temperature difference between the p-layer (or n-layer) surface temperature in step (2) and the substrate heating temperature in step (1) is not 30 ° C. or more, the reaction on the p-layer (or n-layer) surface Is not performed efficiently, and polycrystalline silicon cannot be deposited at high speed. If the temperature difference is 450 ° C. or more, the crystallinity is disturbed, so that the electrical properties are reduced.

(5) Raw Material of Polycrystalline Silicon Thin Film to Be P-Layer (or N-Layer) In the method for manufacturing a photoelectric conversion element according to the second invention of the present application,
Hydrogenated silane used as a raw material of a polycrystalline silicon thin film to be a p-layer (or n-layer) is represented by a general formula Si _n H
_{( 2n + 2)} (however, n is a natural number of 1 or more) and is not particularly limited as long as it can be gasified. Examples of hydrogenated silanes that can be suitably used include SiH ₄ (monosilane), Si ₂ H ₆ (disilane),
Si ₃ H ₈ (trisilane) and the like. In the step (1), the hydrogenated silane may be used as a mixture with a gas of another silane compound such as a halogenated silane. % Is required. If the ratio of the hydrogenated silane is less than 50 mol%, the structure of the obtained thin film is not polycrystalline but an amorphous structure. Cannot be obtained.

Examples of the group III element compound or the group V element compound of the periodic table include B ₂ H ₆ , BF ₃ and PH.
₃ , AsH ₃ , AsF ₅ , PF ₅ , PF ₃ , BCl _{3 and the} like.

(6) Temperature range in which the silane hydride gas is preheated In the method for manufacturing a photoelectric conversion element according to the second aspect of the present invention, the heat energy is increased by preheating the silane silane gas in the step (1). Supplied to the silane silicide molecule to allow a more stable structure to be constructed after deposition on the substrate. In that case, the temperature range in which the hydrogenated silane gas is pre-heated is preferably 400 ° C. or more and 600 ° C. or less. More preferably 450 ° C. or higher 5
50 ° C. or less. By preheating the hydrogenated silane gas to the above temperature range, thermal energy is efficiently supplied to the hydrogenated silane molecules, a more stable structure is formed after the deposition on the substrate, and the p-layer (or n This is because a layer can be formed. In step (2), by preheating a gas containing at least a halogenated silane, the efficiency of film formation can be improved and the productivity can be increased. However, from the viewpoint of the crystallinity of the obtained i-layer, that is, the polycrystalline silicon thin film, at least preheating of the gas containing the halogenated silane is not essential, and the temperature of the gas may be in the range of 15 (about room temperature) to 550 ° C. I just need. This is because the p-layer (or n-layer) having good crystallinity has already been formed in the step (1), and it is not particularly necessary to preheat the gas.

Further, the silane gas can be supplied by mixing with a non-deposition gas such as hydrogen, helium, argon, xenon or the like which does not participate in the deposition of the polycrystalline silicon thin film. When hydrogen is used among the above-mentioned diluent gases, the effect of the present invention is remarkably exhibited. More specifically, a good crystal nucleus is formed when hydrogen is supplied at about 5 to 100 times the flow rate of monosilane in a standard state. Although detailed research has been done on this reason, no clear reason is currently given.

(7) Raw material of i-layer or polycrystalline silicon thin film in step (2) The halogenated silane used as the raw material of the i-layer or polycrystalline silicon thin film in step (2) has at least one halogen atom in the molecule. There is no particular limitation as long as it is a gasifiable silane compound having Suitable halogenated silanes include compounds represented by SiH _m X _(4-m) (where m is an integer of 0 to 3 and X is a fluorine atom, a chlorine atom or a bromine atom). . Specific examples of such a halogenated silane include SiF ₄ (tetrafluorosilane), SiF ₃ H (trifluorofluorosilane),
F ₂ H ₂ (difluorosilane), SiFH ₃ (monofluorosilane), SiCl ₄ (tetrachlorosilane), SiCl ₃
H (trichlorosilane), SiCl ₂ H ₂ (dichlorosilane), SiClH ₃ (monochlorosilane) and the like.

In the step (2), it is important to use such a halogenated silane in order to rapidly deposit a polycrystalline silicon film having excellent crystallinity and high photoconductivity. In the step (2), a gas containing at least such a halogenated silane may be used as a plasma, and the halogenated silane may be mixed with another silane compound gas such as the above-mentioned hydrogenated silane. Can also. At this time, from the viewpoint of the properties of the obtained i-layer, that is, the polycrystalline silicon thin film, the ratio of the halogenated silane to the total silane to be plasmated is preferably 50 mol% or more. In particular, when used in combination with the above-mentioned hydrogenated silane, an i-layer, that is, a polycrystalline silicon thin film having excellent crystallinity and high photoconductivity can be deposited at a higher speed.

Since halogenated silane is used as a raw material in the step (2), the polycrystalline silicon film formed in this step can contain a halogen atom. The light transmittance of the silicon thin film can be increased. Further, it is expected that the conversion efficiency will be further increased by forming a part of the p-layer (or n-layer) as a polycrystalline silicon thin film having a high light transmittance as obtained in this step. The amount of halogen atoms in the polycrystalline silicon thin film formed in this step can be controlled at about 0.005 to 5 atomic%, but a preferable halogen atom content from the viewpoint of transmittance is about 0.01 to 5 atomic%. Preferably, it is 3 atomic%, especially about 0.1-1 atomic%. Further, the halogen atom is preferably a chlorine atom.

The above silane gas can be supplied alone,
It is also possible to supply by diluting with a non-deposition gas such as helium, argon, and xenon which does not participate in the deposition of the polycrystalline silicon thin film. When hydrogen is used among these dilution gases, the effect of the present invention is remarkably exhibited.

(8) Reaction pressure at the time of depositing a polycrystalline silicon thin film Further, the reaction pressure at the time of depositing a polycrystalline silicon thin film in the method for manufacturing a photoelectric conversion element according to the second invention of the present application is:
In the step (1), 1 mTorr or more and 500 mTorr
r or less, 5 mTorr or more and 100 in the step (2).
0 mTorr or less, and the reaction pressure in the step (2) is more preferably 3 to 80 than the reaction pressure in the step (1).
A favorable result can be obtained by setting 0 mTorr higher.

If the reaction pressure in the step (1) is less than 1 mTorr, stable plasma cannot be formed, which causes a problem in production. On the other hand, when the pressure exceeds 500 mTorr, the raw material gas is agglomerated, so that powder is generated in the plasma, which causes point defects in the film and lowers the production yield.

If the reaction pressure in the step (2) is less than 5 mTorr, the effect of the present invention cannot be exhibited because the deposition rate of the i-layer, that is, the polycrystalline silicon thin film is reduced. On the other hand, when the pressure exceeds 1000 mTorr, it is difficult to form plasma stably, which causes a problem in manufacturing.

If the reaction pressure in the step (2) is not higher than the reaction pressure in the step (1) by 3 mTorr or more, it is difficult to increase the deposition rate of the i-layer, that is, the polycrystalline silicon thin film. If the reaction pressure in the step (2) is higher than the reaction pressure in the step (1) by more than 800 mTorr, the crystallinity tends to be disordered.

(9) Method for Heating Source Gas In the step (1) and, if necessary, the step (2), the method for heating the source gas may be any known means without particular limitation. That is, a method in which a gas pipe is directly heated by a heater, a method in which a gas pipe is heated by high-frequency induction heating, and a preliminary chamber provided with a gas heater in advance,
A method of preheating with an infrared lamp or the like is suitably employed without any particular limitation.

(10) Temperature Measurement and Adjustment In step (1), it is difficult to accurately measure the temperature of the hydrogenated silane gas in advance. Therefore, at present, the gas pipe temperature is used as the gas temperature. The length is set to be long enough to make the temperature uniform. In addition, when heating the hydrogenated silane gas by a heater (for example, 6a in FIG. 1) in the reaction vessel, the present inventors consider the physical properties of the obtained polycrystalline silicon film and the hydrogenated silane gas heated as described above. It has been confirmed that the set temperature of the heater can be used as the gas temperature based on the correlation with the heating temperature of the silane gas. In addition, when heating the gas in the step (2), the gas temperature can be adjusted in the same manner.

(11) Management of Utilization In the method for manufacturing a photoelectric conversion element according to the second invention of the present application, the steps (1) and (2) are performed based on the total supply amount of all silanes used in each step. By controlling the “utilization rate” defined by the amount of polycrystalline silicon formed in each step, a photoelectric conversion element made of a polycrystalline silicon thin film having extremely few defects can be efficiently manufactured. Here, the utilization rate is calculated by the following equation.

[0077]

(Equation 2)

In the above formula, all silanes used in each step mean all silanes serving as a source of Si atoms. In step (1), hydrogenated silanes which can be used together with hydrogenated silanes are used in step (1). And all other silanes such as hydrogenated silanes which can be used in combination with the halogenated silanes in the step (2). In the above formula, the "total supply amount of all silanes" and the "amount of polycrystalline silicon formed in each step" are both expressed on the basis of Si atoms (the number of Si atoms).

When the utilization is low, the production efficiency of the polycrystalline silicon thin film is reduced. On the other hand, when the utilization is excessive, decomposition products which adversely affect the deposition of the film are generated. This adheres to the base material or the p-layer (or n-layer) and becomes a physical defect, deteriorating the crystallinity. The preferred range of utilization depends on the composition of the silane gas used and the purpose of utilization control. The purpose of the utilization control in the method for manufacturing a photoelectric conversion element of the second invention of the present application is as follows.
Is mentioned. A p-layer (or n-layer) made of a polycrystalline silicon thin film serving as a seed crystal is formed. A p-layer (or n-layer) made of a polycrystalline silicon thin film is grown. An i-layer, that is, a polycrystalline silicon thin film is deposited at a high speed on the p-layer (or n-layer).

In order to efficiently obtain a polycrystalline silicon thin film having good crystallinity, the utilization in the steps (1) and (2) is set to about 0.5 to 10% and about 10 to 80%, respectively.
, Particularly preferably about 1 to 5% and about 30 to respectively.
It is better to manage within the 60% range. The above utilization rate is the supply rate or temperature of the silane used in each step, the supply rate or temperature when a diluting gas is used, the temperature of the substrate or p-layer (or n-layer), the pressure in the reactor, or the plasma. It can be controlled by one or more of the energy amounts added for generation.

(10) Substrate used in the method for producing a photoelectric conversion element according to the second invention of the present application The substrate used in the present invention is not particularly limited, and may be selected according to the solar cell forming process and application. Is appropriately selected. For example, when used as a photoelectric conversion layer of a solar cell, as a substrate, quartz glass, blue plate glass, single crystal silicon, polycrystalline silicon,
Various metals, heat-resistant polymers, transparent conductors and the like can be used.

(11) Other manufacturing conditions in the method of manufacturing the photoelectric conversion element of the second invention of the present application In the method of manufacturing the photoelectric conversion element of the second invention of the present application,
As for the deposition of the polycrystalline silicon thin film, a known method is used without particular limitation as long as the above-mentioned production conditions are satisfied. For example, as a means for converting the raw material gas into plasma in the steps (1) and (2), a known method such as a high frequency, an ultrashort wave, a low frequency, or a microwave is used without particular limitation.

(12) Heat treatment of p-layer (or n-layer) in the process of manufacturing the photoelectric conversion element In the method of manufacturing the photoelectric conversion element of the second invention of the present application, after forming the p-layer (or n-layer), P for layer (or n-layer)
Heat treatment at a temperature equal to or higher than the formation temperature of the layer (or n-layer),
Thereafter, the step (2) can be performed. Thereby, the heat resistance and the plasma resistance of the p layer (or n layer) formed in the step (1) are improved, and then the p layer (or n layer) is improved.
An i-layer can be formed on the layer in step (2). When the i-layer is formed at a high temperature in step (2), impurities in the p-layer (or n-layer) diffuse into the i-layer. An inert layer is generated at the p / i interface, thereby preventing the initial conversion efficiency from decreasing. Further, the obtained i-layer shows stable carrier transportability even when irradiated with light, and the deterioration is suppressed. The above heat treatment temperature is preferably set to 200 ° C. to 600 ° C. When the heat treatment temperature is lower than 200 ° C., the heat resistance and the plasma resistance of the p-layer (or n-layer) cannot be sufficiently improved. The crystallinity of the (or n-layer) is disturbed, which is not preferable.

C. The polycrystalline silicon thin film of the third invention of the present application The polycrystalline silicon thin film of the third invention of the present application
Produced by applying the method for producing a polycrystalline silicon thin film according to the present invention, having a characteristic that the crystal volume fraction is about 85% or more and the dark conductivity is about 1 × 10 ⁻³ or more. The features thereof, and therefore, the conditions applied to the method of manufacturing the polycrystalline silicon thin film of the first invention of the present application are similarly applied as the conditions for manufacturing the polycrystalline silicon thin film of the third invention of the present application. . This will be specifically described below.

That is, the polycrystalline silicon thin film of the third invention of the present application comprises a polycrystalline silicon base layer obtained by performing the first step of the first invention of the present application and a polycrystalline silicon thin film obtained by performing the second step. It consists of a crystalline silicon thin film main layer. That is, the polycrystalline silicon thin film of the third invention of the present application comprises a polycrystalline silicon base layer formed on a substrate by converting a hydrogenated silane gas into plasma and contacting the substrate with at least a polycrystalline silicon base layer. A polycrystalline silicon thin film comprising a polycrystalline silicon thin film main layer formed by plasma-forming a gas containing a halogenated silane and having a crystal volume fraction of about 85% or more and a dark conductivity of about 1 × 10 5 ^-3 or more polycrystalline silicon thin film.

(1) Crystal Volume Fraction of Polycrystalline Silicon Thin Film of the Third Invention of the Present Application The polycrystalline silicon thin film of the third invention of the present application is characterized as having a crystal volume fraction of about 85% or more. Can be Here, when the crystal volume fraction is not more than about 85%, as a result of insufficient crystallinity, the photoconductivity decreases due to an increase in the crystal defect density, and the conversion efficiency decreases.

(2) Dark Conductivity of the Polycrystalline Silicon Thin Film of the Third Invention of the Present Application The polycrystalline silicon thin film of the third invention of the present application is characterized by having a dark conductivity of about 1 × 10 ⁻³ or more. Attached. If the dark conductivity is not more than about 1 × 10 ⁻³ , the conversion efficiency is reduced as a result of insufficient conductivity.

The above-described characteristics of the polycrystalline silicon thin film of the third invention of the present application are as follows: the polycrystalline silicon thin film of the third invention of the present application is manufactured by the manufacturing method specified as the first invention of the present application. This is achieved because crystal defects caused by dust such as powder and flakes generated in plasma during the manufacturing process can be significantly reduced. Moreover, the polycrystalline silicon thin film of the third invention of the present application is:
While exhibiting such excellent crystallinity and electrical characteristics, it is not simply produced in a laboratory but can be produced extremely efficiently in an actual industrial production process. Therefore, in that respect, the characteristics of the polycrystalline silicon thin film of the third invention of the present application are technically different from the characteristics of the polycrystalline silicon thin film simply produced in a laboratory without particularly considering production efficiency and the like. As significant, it must be distinguished from the characteristics of a polycrystalline silicon thin film simply produced in a laboratory.

D. The photoelectric conversion element of the fourth invention of the present application The photoelectric conversion element of the fourth invention of the present application is manufactured by applying the method of manufacturing the photoelectric conversion element of the second invention of the present application, and has a quantum efficiency of 0 at a wavelength of 400 nm. 0.7 or more, and the ratio of the conversion efficiency after 20000 spectral irradiation to the initial conversion efficiency is about 0.95 or more. Various conditions applied to the method for manufacturing the conversion element are similarly applied as conditions for manufacturing the photoelectric conversion element of the fourth invention of the present application. This will be specifically described below.

That is, the photoelectric conversion element according to the fourth invention of the present application comprises a p-layer (or n-layer) obtained by performing the step (1) of the second invention of the present application, and a step (2). I obtained
Layer and n-layer (or p-layer) obtained by performing step (3)
And That is, the photoelectric conversion element according to the fourth invention of the present application is a method in which a gas mixture of hydrogenated silane and a group III element compound of the periodic table (or a group V element compound of the periodic table) is converted into plasma and brought into contact with the substrate. On the base material
A p-layer (or n-layer) having a thickness of about 10 to 150 angstroms obtained by depositing polycrystalline silicon containing a group I element (or a group V element of the periodic table), and a gas containing at least a halogenated silane Plasma is generated and the p layer (or n
Layer), a mixed gas of at least one of a silane of hydrogenated silane and a halogenated silane and a Group V element compound of the Periodic Table (or a Group III element compound of the Periodic Table) Is formed into a plasma, and is brought into contact with the i-layer to deposit polycrystalline silicon containing a Group V element of the periodic table (or a Group III element of the periodic table) on the i-layer, thereby forming an n-layer (or p-layer). Layer), wherein the quantum efficiency at a wavelength of 400 nm is 0.7 or more, and the ratio of the conversion efficiency after 20000 spectral irradiation to the initial conversion efficiency is about 0.95 or more. This is a characteristic photoelectric conversion element.

The photoelectric conversion element according to the fourth invention of the present application is:
Crystalline defects caused by dust such as powders and flakes generated in plasma during the manufacturing process are extremely small, and have excellent crystallinity and electrical characteristics, and are applied as silicon-based thin-film solar cells with high performance and high reliability. be able to.

(1) Quantum Efficiency of Photoelectric Conversion Element of the Fourth Invention of the Present Application The photoelectric conversion element of the fourth invention of the present application is characterized as having a quantum efficiency of 0.7 or more at a wavelength of 400 nm. Here, the quantum efficiency at a wavelength of 400 nm is 0.
When it is not more than 7, the light absorption characteristics are not sufficient, and the light absorption characteristics are only about the same as those of the solar cell obtained by the conventional technology, and it is not recognized that the solar cell is particularly useful.

(2) Ratio of conversion efficiency after irradiation of light for a certain time with respect to the initial conversion efficiency of the photoelectric conversion element of the fourth invention of the present application The photoelectric conversion element of the fourth invention of the present application has a conversion efficiency of 20,000 with respect to the initial conversion efficiency. Conversion efficiency ratio after spectral irradiation is about 0.9
It is characterized as having five or more. Here, when the ratio of the conversion efficiency after the 20,000 spectral irradiation to the initial conversion efficiency is not more than about 0.95, the light deterioration characteristic is not sufficient, and the light deterioration characteristic is the light of the photoelectric conversion element obtained by the conventional technique. The performance is equivalent to the deterioration characteristic, and the durability when applied as, for example, a solar cell becomes insufficient.

The characteristics possessed by the photoelectric conversion element of the fourth invention of the present application are as follows as a result of the photoelectric conversion element of the fourth invention of the present application being manufactured by the manufacturing method specified as the second invention of the present application. This is achieved by remarkably reducing crystal defects caused by dust such as powder and flakes generated in plasma during the manufacturing process. Moreover, the photoelectric conversion element of the fourth invention of the present application, while exhibiting such extremely excellent crystallinity and electric characteristics, is not simply manufactured in a laboratory, but is extremely efficient in actual industrial production processes. It can be produced well. Therefore, in that respect, the characteristics of the photoelectric conversion element of the fourth invention of the present application are different in technical significance from the characteristics of the polycrystalline silicon thin film simply manufactured in a laboratory without particularly considering production efficiency and the like. Must be recognized separately from the characteristics of a photoelectric conversion element manufactured simply in a laboratory.

[0095]

EXAMPLES In order to more specifically explain the present invention, examples of the method for manufacturing a polycrystalline silicon thin film and the method for manufacturing a photoelectric conversion element according to the present invention will be described below. Each of the following examples was performed using a polycrystalline silicon thin film manufacturing apparatus schematically shown in FIG. In the following examples and comparative examples,
Conductivity evaluation, crystallinity evaluation, light resistance deterioration test, quantum efficiency evaluation and chlorine content evaluation of the polycrystalline silicon thin film obtained by the present invention were performed by the following methods (1) to (5).

(1) Conductivity As shown in FIG. 2, a gap type metal electrode 14 is formed on the polycrystalline silicon film 13 deposited on the quartz substrate 5 so as to form an ohmic contact. The current flowing in a state where a voltage was applied was measured to determine the conductivity. The conductivity in a dark state without light irradiation was defined as dark conductivity, and the conductivity in a state irradiated with light was defined as photoconductivity. Light intensity is 1
00 mW / cm ² .

(2) Crystallinity The wavelength dependence of the pseudo dielectric constant is measured by a spectroscopic ellipsometer using a wavelength in the ultraviolet to visible region, and the obtained waveform is analyzed based on Blackman's theory of effective medium approximation. Thus, the crystal volume fraction of the polycrystalline silicon film was estimated.

(3) Light Resistance Deterioration Test A sample was irradiated with a xenon lamp light of 500 mW / cm ² with infrared light of 2,000 nm or more blocked by a filter, and the light irradiation time dependency of the photoconductivity was examined. At this time, the light irradiation time was fixed at 20,000 minutes. In order to prevent the temperature of the sample from rising during light irradiation, the sample holder was cooled with water, and the surface temperature of the sample was always 40 ° C. The ratio of the conversion efficiency after 20,000 spectral irradiation to the initial conversion efficiency was evaluated as the degree of light resistance deterioration of the photoconductivity. In the case of performing a light resistance deterioration test of a solar cell, a pin (nip) type polycrystalline silicon film is deposited on a transparent electrode of a glass substrate with a transparent electrode, and a silver electrode is further adhered thereon by vacuum deposition. Then, the degree of light deterioration of the conversion efficiency was examined. The degree of light resistance deterioration of the conversion efficiency is the ratio of the conversion efficiency after 20,000 spectral irradiation to the initial conversion efficiency as in the case of the photoconductivity.

(4) Measurement of Quantum Efficiency of Solar Cell The quantum efficiency at a wavelength of 400 nm was obtained by measuring the current-voltage characteristics of the solar cell in the wavelength range of 400 to 800 nm.

(5) Halogen atom content in polycrystalline silicon thin film Measurement of halogen atom content in polycrystalline silicon thin film
Using a secondary ion detection mass spectrometer, a sample deposited on a quartz substrate was subjected to the main layer from the surface side of the deposited film.

Example 1 As a gas for depositing a polycrystalline silicon thin film in the first step, 3 sccm of monosilane gas and 50 sccm of hydrogen gas were introduced into the reaction vessel 1. The monosilane gas is 4
Preheating was performed to 50 ° C. Then, after the pressure in the reaction vessel 1 was set to 100 mTorr by the pressure regulator 9, plasma was generated by gas or the like. A high-frequency power supply is used as the power supply for plasma generation, and the output is 2
Adjusted to 0W. The shutter 12 was closed for about 10 seconds until the plasma was stabilized, and after 10 seconds, the shutter 12 was opened, and the heating base 5 was brought into contact with the plasma to deposit a polycrystalline silicon thin film base layer on the base 5. . At that time, the substrate temperature was 150 ° C., and the deposition time was 200 seconds. Quartz glass was used for the substrate. Here, by setting the deposition time to 200 seconds under the above conditions, about 100
The correspondence between the deposition time and the thickness of the polycrystalline silicon thin film having a thickness of Å was confirmed in advance, and the above-mentioned thin film was deposited.

The deposition of the polycrystalline silicon thin film base layer in the first step is terminated by closing the shutter 12 and stopping the deposition of the polycrystalline silicon film on the substrate 5.
The temperature of the base layer formed on the substrate 5 was raised to 250 ° C., and dichlorosilane gas was supplied into the reaction vessel 1 at a flow rate of 10 sccm. Monosilane gas was introduced into the reaction vessel 1 at the same flow rate as in the first step without preheating using a bypass line. After the pressure in the reaction vessel 1 was set to 200 mTorr by the pressure adjuster 9, plasma by gas was generated. As in the first step, a high-frequency power source was used as a power source for plasma generation, and the output was adjusted to 100 W. Approximately 10 until plasma stabilizes
Shutter 12 is closed for 10 seconds and shutter 1
2 was opened, and a second step of depositing a polycrystalline silicon thin film on the substrate by contacting the plasma with the polycrystalline silicon film base layer on the heating substrate obtained in the first step was performed. The deposition time was 1000 seconds. 1 as in the first step
It has been previously confirmed that a polycrystalline silicon thin film having a thickness of about 3.5 μm can be obtained by deposition for 2,000 seconds.

The characteristics of the obtained polycrystalline silicon thin film were a crystal volume fraction of 85% and a dark conductivity of 1 × 10 ⁻³ S / cm or more. As a result of the light deterioration test, the light deterioration degree of the conversion efficiency was 0.1.
The conversion efficiency was 95, and almost no decrease in conversion efficiency due to light irradiation was observed. The chlorine content was 0.5 atomic%.

Example 2 In Example 1, a polycrystalline silicon thin film was deposited by changing only the heating temperature of the monosilane gas in the first step to 550 ° C. and fixing other conditions. The obtained polycrystalline silicon thin film was evaluated in the same manner as in Example 1. As a result, the crystal volume fraction was 93% and the dark conductivity was 5 × 10 ⁻³ S / cm or more. As a result of performing a light deterioration test in the same manner as in Example 1, the degree of light deterioration resistance of the conversion efficiency was 0.96, and almost no decrease in the conversion efficiency due to light irradiation was observed. Further, the chlorine content was 0.3 atomic%.

Example 3 In Example 1, the temperature of the substrate in the first step was set to 250.
° C, the substrate temperature in the second step was changed to 300 ° C,
The other conditions were fixed, and a polycrystalline silicon thin film was deposited. The obtained polycrystalline silicon thin film was evaluated in the same manner as in Example 1. As a result, the crystal volume fraction was 90% and the dark conductivity was 5 × 10 ⁻³ S / cm or more. As a result of performing a light degradation test in the same manner as in Example 1, the light resistance degradation degree of conversion efficiency was 0.9
6, and a decrease in conversion efficiency due to light irradiation was hardly observed. Further, the chlorine content was 0.3 atomic%.

Example 4 In Example 1, the temperature of the substrate in the first step was set to 250.
° C, the substrate temperature in the second step was changed to 500 ° C,
The other conditions were fixed, and a polycrystalline silicon thin film was deposited. The obtained polycrystalline silicon thin film was evaluated in the same manner as in Example 1. As a result, the crystal volume fraction was 93% and the dark conductivity was 5 × 10 ⁻³ S / cm or more. As a result of performing a light degradation test in the same manner as in Example 1, the light resistance degradation degree of conversion efficiency was 0.9
The conversion efficiency was almost not reduced due to light irradiation. The chlorine content was 0.6 atomic%.

Example 5 Diborane gas (B ₂ H ₆ ) was mixed with hydrogen gas supplied in the first step of Example 1 at a flow rate of 0.3 sccm.
The other conditions were fixed and the first step was performed to form a P-type polycrystalline silicon thin film. At this time, quartz glass with a transparent electrode was used as a substrate. After that, the second step was performed in the same manner as in Example 1 to deposit a polycrystalline silicon thin film containing no impurity at 3.5 μm. After completion of the second step, the shutter 12 is closed to stop the deposition of the polycrystalline silicon film on the base material, and the hydrogen gas being supplied is supplied with phosphine gas (P
H ₃ ) was mixed at a flow rate of 0.3 sccm, and the other conditions were the same as in the second step to deposit an N-type polycrystalline silicon thin film having a thickness of 100 Å.

When all the steps have been completed, the substrate temperature is set to 50 ° C.
After being lowered to the extent, the substrate on which the polycrystalline silicon thin film has been deposited is taken out of the reaction vessel 1, and a silver electrode is deposited on the uppermost N-type polycrystalline silicon film by a vacuum deposition method to form a PIN type polycrystalline silicon thin film solar cell. A battery was formed. When the photoelectric conversion efficiency of the obtained solar cell was measured, a conversion efficiency of about 8% was obtained. As a result of performing a light deterioration test on the solar cell in the same manner as in Example 1, the light resistance deterioration degree of the conversion efficiency was 0.96, and almost no decrease in the conversion efficiency due to light irradiation was observed. The quantum efficiency at a wavelength of 400 nm is 0.77.
Met.

Example 6 The procedure of Example 5 was repeated except that the P-type polycrystalline silicon thin film obtained by performing the first step before performing the second step had a thickness of 25%.
When the photoelectric conversion efficiency of the solar cell obtained by performing the heat treatment at 0 ° C. for 1 hour was measured, a conversion efficiency of about 9% was obtained.
As a result of performing a light deterioration test on the solar cell in the same manner as in Example 1, the light resistance deterioration degree of the conversion efficiency was 0.98, and a decrease in the conversion efficiency due to light irradiation was hardly observed. The quantum efficiency at a wavelength of 400 nm was 0.80.

Example 7 The first step was carried out by mixing phosphine gas (PH ₃ ) at a flow rate of 0.3 sccm with the hydrogen gas supplied in the first step of Example 1 and fixing other conditions. Sa5
A 0 Å N-type polycrystalline silicon thin film was formed. At this time, quartz glass with a transparent electrode was used as a substrate. After that, the second step was performed in the same manner as in Example 1 to deposit a polycrystalline silicon thin film containing no impurity at 3.5 μm. At that time, in the second step, the above-mentioned dopant was mixed up to 100 angstroms on the N-type polycrystalline silicon thin film to deposit a polycrystalline silicon thin film. Therefore, the thickness of the N-type polycrystalline silicon thin film is 150 Å in total. After the second step, the shutter 12
Is closed, the deposition of the polycrystalline silicon film on the base material is stopped, and diborane gas (B ₂ H ₆ ) is added to the hydrogen gas being supplied.
A P-type polycrystalline silicon thin film having a thickness of 100 Å was deposited in the same manner as in the second step except for mixing at a flow rate of 3 sccm. After all the steps have been completed and the substrate temperature has dropped to about 50 ° C., the substrate on which the polycrystalline silicon thin film has been deposited is taken out of the reaction vessel 1 and a silver electrode is placed on the uppermost P-type polycrystalline silicon film. The NIP-type polycrystalline silicon thin-film solar cells were formed by vacuum deposition. When the photoelectric conversion efficiency of the obtained solar cell was measured, it was about 8%.
Conversion efficiency was obtained.

As a result of performing a light deterioration test on the solar cell in the same manner as in Example 1, the degree of light resistance deterioration of the conversion efficiency was 0.97, and almost no decrease in the conversion efficiency due to light irradiation was observed. The quantum efficiency at a wavelength of 400 nm is 0.75.
Met. Further, the measurement of the chlorine content of the p-layer in the solar cell of this embodiment was performed using a sample in which the p-layer was deposited on a quartz substrate under the same deposition conditions as those of the p-layer in this embodiment. I went. The measurement was performed using a secondary ion detection mass spectrometer for the main layer from the surface side of the deposited film of this sample. As a result, the chlorine content was 0.3 atomic%.

Comparative Example 1 In Example 1, a polycrystalline silicon thin film was deposited without heating the monosilane gas in the first step and fixing other conditions. When the obtained polycrystalline silicon thin film was evaluated in the same manner as in Example 1, the crystal volume fraction was 8
It was about 0% and the dark conductivity was about 5 × 10 ⁻⁴ S / cm, showing almost the same quality as the polycrystalline silicon thin film obtained by the conventional technique. Further, when the surface condition of the film surface was visually observed, it was white and cloudy, and pinholes were observed. In addition, as a result of performing a light deterioration test in the same manner as in Example 1, it was observed that the light resistance deterioration degree of the conversion efficiency was 0.94, and that the reduction in the conversion efficiency due to light irradiation was larger than that of each example. Was.

Comparative Example 2 In Example 1, the polysilane thin film was deposited while the heating temperature of the monosilane gas in the first step was 650 ° C. and the other conditions were fixed. When the obtained polycrystalline silicon thin film was evaluated in the same manner as in Example 1, the crystal volume fraction was 80% and the dark conductivity was about 5 × 10 ⁻⁴ S / cm.
It showed almost the same quality as the polycrystalline silicon thin film obtained by the conventional technology. Further, when the surface condition of the film surface was visually observed, it was white and cloudy, and pinholes were observed. In addition, as a result of the light deterioration test performed in the same manner as in Example 1, the light resistance deterioration degree of the conversion efficiency was 0.92. Was.

Comparative Example 3 In Example 1, the deposition time in the first step was set to 10 seconds, and the other conditions were fixed to deposit a polycrystalline silicon thin film. It has been previously confirmed that a polycrystalline silicon thin film having a thickness of about 5 angstroms can be obtained by deposition for 10 seconds. When the obtained polycrystalline silicon thin film was evaluated in the same manner as in Example 1, the crystal volume fraction was 75% and the dark conductivity was 5
It was about × 10 ⁻⁴ S / cm, and showed almost the same quality as the polycrystalline silicon thin film obtained by the conventional technique. Further, when the surface condition of the film surface was visually observed, it was white and cloudy, and pinholes were observed. In addition, as a result of performing a light deterioration test in the same manner as in Example 1, the light resistance deterioration degree of the conversion efficiency was 0.3.
It was 91, and it was observed that the reduction in conversion efficiency due to light irradiation was greater than that in each of the examples.

[0115]

As will be understood from the above description, according to the polycrystalline silicon thin film and the photoelectric conversion element of the present invention and their manufacturing method, a high quality film having excellent crystallinity and electrical characteristics can be obtained at a high film forming speed. It becomes possible to manufacture a polycrystalline silicon thin film and a photoelectric conversion element, and it is possible to industrially produce a solar cell using the polycrystalline silicon thin film, which is a technique which greatly contributes to the industrialization. The polycrystalline silicon thin film and the photoelectric conversion element of the present invention and the method of manufacturing the same not only reduce the manufacturing time, but also do not generate a defect source such as powder as a by-product in plasma during the manufacturing, so that the manufacturing apparatus The industrial value is extremely large because the maintenance is simplified and the polycrystalline silicon thin film can be deposited with good yield.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a typical embodiment of an apparatus used to carry out the present invention.

FIG. 2 is a conceptual diagram of an element for measuring a spectral characteristic and for a light resistance deterioration test.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction container 2 High frequency application electrode 3 Ground electrode 4 High frequency generator 5 Substrate 6 Heater 7 Gas supply port 8 Vacuum pump 9 Pressure regulator 10 Gas tube heater 12 Shutter 13 Polycrystalline silicon thin film obtained by the present invention 14 Metal electrode

Claims (8)

[Claims] 1. A first step of forming a polycrystalline silicon base layer on a substrate by converting a hydrogenated silane gas into a plasma and bringing the same into contact with the substrate, and converting the gas containing at least a halogenated silane into a plasma, A second step of depositing a polycrystalline silicon thin film on a silicon base layer. 2. The method according to claim 1, wherein the thickness of the polycrystalline silicon base layer formed in the first step is determined by the crystallinity of the polycrystalline silicon base layer to determine the crystallinity of the polycrystalline silicon thin film deposited in the second step. 2. The method for producing a polycrystalline silicon thin film according to claim 1, wherein the thickness is set to be not less than the thickness and not more than 150 angstroms. 3. In the first step and the second step, the amount of polycrystalline silicon formed in each step with respect to the total supply amount of all silanes used in each step (hereinafter referred to as “utilization rate”). 3. The method for producing a polycrystalline silicon thin film according to claim 1, wherein 4. The method for producing a polycrystalline silicon thin film according to claim 3, wherein the utilization in the first step is 0.5 to 10%, and the utilization in the second step is 10 to 80%. 5. A p-layer (or n-layer), i-layer and n-layer on a substrate.
A method for manufacturing a photoelectric conversion element in which layers (or p-layers) are laminated in this order, comprising the following steps (1) to (3). (1) A mixed gas of hydrogenated silane and a Group III element compound of the Periodic Table (or a Group V element compound of the Periodic Table) is converted into a plasma and brought into contact with the substrate to form a plasma on the substrate. A step of forming a p-layer (or n-layer) having a thickness of about 10 to 150 angstroms by depositing polycrystalline silicon containing a group V element (or a group V element of the periodic table) (2) including at least a halogenated silane The gas is turned into a plasma and brought into contact with the p-layer (or n-layer) to form p-type gas.
Step of depositing polycrystalline silicon on layer (or n-layer) to form i-layer (3) At least one of hydrogenated silane or halogenated silane and Group V element compound of periodic table (or periodicity) The mixed gas of the group III element in the periodic table is turned into plasma and brought into contact with the i-layer formed in the step (2) to form a group V element in the periodic table (or group III in the periodic table) on the i-layer.
Forming an n-layer (or p-layer) by depositing polycrystalline silicon containing a group element). 6. The step of forming a p-layer (or n-layer) comprises converting a mixed gas of hydrogenated silane and a group III element compound of the periodic table (or a group V element compound of the periodic table) into plasma, A p-layer 1 (or an n-layer 1) by depositing polycrystalline silicon containing a group III element of the periodic table (or a group V element of the periodic table) on the substrate by contacting the material; A mixed gas of at least a halogenated silane and a group III element compound of the periodic table (or a group V element compound of the periodic table) is converted into a plasma and brought into contact with the p layer 1 (or the n layer 1) to form the p layer 1 (or A p-layer 2 (or n-layer 2) containing a Group III element of the periodic table (or a Group V element of the periodic table) is formed on the n-layer 1), and the p-layer 1 and the p-layer 2 (or the n-layer 1) are formed. Or a step of forming a p-layer (or n-layer) having a thickness of about 10 to 150 angstroms comprising the n-layer 2). The method of producing a photoelectric conversion element Motomeko 5 wherein. 7. A polycrystalline silicon base layer formed on a base material by converting a hydrogenated silane gas into a plasma and contacting the base material, and a gas containing at least a halogenated silane on the polycrystalline silicon base layer. A polycrystalline silicon thin film comprising a polycrystalline silicon thin film main layer deposited and deposited, wherein the polycrystalline silicon thin film has a crystal volume fraction of about 85% or more and a dark conductivity of about 1 × 10 ⁻³ or more. . 8. A gas mixture of hydrogenated silane and a Group III element compound of the Periodic Table (or a Group V element compound of the Periodic Table) is turned into plasma and brought into contact with the substrate to form a periodic table on the substrate. The thickness obtained by depositing polycrystalline silicon containing a group III element (or a group V element in the periodic table) is about 10 to 15
A 0-angstrom p-layer (or n-layer), an i-layer formed by converting a gas containing at least a halogenated silane into plasma, and contacting the p-layer (or n-layer) with at least a hydrogenated silane or a halogenated silane Any one of the silanes and the Group V element compounds of the periodic table (or
The mixed gas of the group II element compound) is turned into plasma, and is brought into contact with the i layer to deposit polycrystalline silicon containing a group V element of the periodic table (or a group III element of the periodic table) on the i layer. A photoelectric conversion element comprising an n-layer (or a p-layer) formed, wherein the quantum efficiency at a wavelength of 400 nm is 0.7 or more, and the quantum efficiency relative to the initial conversion efficiency is 200
A photoelectric conversion element, wherein the conversion efficiency ratio after the 00 spectral irradiation is about 0.95 or more.