JP2003347221A - Cat-PECVD METHOD, FILM FORMED BY THE SAME AND THIN FILM DEVICE HAVING THE FILM - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method which forms a film in high uniformity in a film thickness and film quality ranging over a large area at a high speed and high quality and obtains high productivity, and a film formed by the same, and a thin film device using the film. <P>SOLUTION: Raw material system gas containing gas containing Si and/or C in a molecular formula and non-Si non-C system gas which is heated by a heat catalyst arranged in a gas introduction path and is composed of gas not containing Si and C in a molecular formula are isolated, respectively. A plurality of gas injection nozzles are provided in an antenna electrode so as to pass the hollow part of the antenna electrode having a hollow structure installed in a film forming space. Gas is injected from the gas injection nozzles to the film forming space and is mixed by being injected to the film forming space. The gas is decomposed and activated by plasma generated by the antenna electrode connected to a high-frequency power source, and a film is deposited on a substrate disposed opposing the antenna electrode in the film forming space. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CVD (Chemical Vapor
or Deposition) PECVD (Plasma Enhanced)
Chemical Vapor Deposition (plasma CVD) method,
CV using a thermal catalyst as a means for decomposing and activating film forming gas
Cat-CVD (Catalytic Chemical Vapor)
Deposition: Cat-PECVD, which is a new CVD method that has not been used in the past, and a film formed by using the method, which combines the catalytic CVD method (the same principle as the HW-CVD method). With regard to thin film devices formed using the film, in particular, it is possible to form a Si-based thin film in a photoelectric conversion device typified by a thin-film Si-based solar cell at high speed and with high quality, and with a uniform film thickness and uniform film quality over a large area, Further, the present invention relates to a technique capable of forming a film with extremely high productivity.

[0002]

[Prior art and its problems] High quality and high speed film forming technology
It is indispensable for high performance and low cost of various thin film devices. In particular, in thin film Si solar cells, which are representative of photoelectric conversion devices, in addition to high quality and high speed film formation of Si films,
Large-area film formation and high productivity are also required at the same time.

[0003] As low-temperature film-forming methods for Si-based thin films, PECVD and Cat-CVD are widely known so far, and both are active mainly in the formation of hydrogenated amorphous silicon films and crystalline silicon films. R & D is being carried out.

FIG. 9 shows a conventional example 1 of a PECVD apparatus.
FIG. 10 shows a Cat-CVD apparatus as Conventional Example 2. 9, 500 is a shower head, 501 is a gas inlet,
502 is a gas ejection port, 503 is a plasma space, 504 is a plasma generation electrode, 505 is a high frequency power supply, 506 is a substrate, 507 is a substrate heating heater, 508 is a gas exhaust vacuum pump, and 509 is an insulating member for electrical insulation. is there. 10, 600 is a shower head, 601 is a gas inlet, 602 is a gas outlet, 603 is an active gas space,
604 is a thermal catalyst, 605 is a power supply for heating the thermal catalyst, 6
Reference numeral 06 denotes a substrate, 607 denotes a substrate heating heater, and 608 denotes a gas exhaust vacuum pump.

Here, SiH ₄ gas and H ₂ gas are used to form Si
Taking the case of forming a film as an example, the PECV shown in FIG.
In the D apparatus, the gas introduced from the gas inlet 501 provided in the shower head 500
2 to the plasma space 503, and the plasma space 5
At 03, excitation is activated to produce a deposited species, which is deposited on the opposing substrate 506 to form a Si film. Here, the plasma is generated by using a high frequency power supply 505.

[0006] In the Cat-CVD apparatus shown in FIG.
The gas introduced from 01 is guided from the gas ejection port 602 to the film forming space, and is activated by the thermal catalyst 604 installed in the film forming space to form the active gas space 603 and deposit the seeds. This is deposited on the opposing substrate 606 to form a Si film. Here, the heating of the thermal catalyst 604 is performed by
This is realized by using the heating power supply 605.

However, these conventional techniques have the following problems. That is, in the PECVD method, in order to realize a high-speed film formation, it is necessary to increase the plasma power to promote the decomposition of the SiH ₄ gas or the H ₂ gas. This is nothing more than increasing the electron temperature Te in the inside (the plasma potential Vp increases in proportion to Te). On the other hand, the ion bombardment on the film formation surface is increased, and SiH ₂ is increased.
This has led to the promotion of the production of higher order silanes (eventually the promotion of the production of powder) due to the increase in the production rate of molecules, and it was inevitable to introduce elements that go against the improvement of quality.

Here, if the plasma excitation frequency is set to the VHF band or higher instead of increasing the plasma power, the ion bombardment is reduced by reducing the plasma potential Vp, and the high quality of the hydrogenated amorphous silicon film or crystalline silicon film is improved. Although effective for film formation (J. Meier et al, Te
chnical digest of 11th PVSEC (1999) p. 221, O. Vet
terl et al, Technical digest of 11th PVSEC (1999)
p. 233), formation of a crystalline Si film requires sufficient generation of atomic hydrogen.
Even if the HF band frequency is used, if a high-speed film formation of a certain level or more is required, an increase in plasma power cannot be avoided.
After all, the inconvenience of the problem described above was unavoidable.

[0009] Therefore, as a measure to increase the atomic hydrogen density without increasing the plasma power, to increase the hydrogen dilution ratio, i.e., it is conceivable to increase the gas flow rate ratio H ₂ / SiH _4, which in the SiH ₄ gas Since the partial pressure is lowered, and if this is the case, it is in a direction opposite to high-speed film formation, so that eventually, the plasma power must be increased to promote the decomposition of SiH ₄ , and the above-mentioned problem cannot be avoided. Was.

In order to reduce the ion bombardment even if the plasma power is increased, it is conceivable to increase the film forming pressure. In this method, it is also difficult to eliminate factors for reducing the film quality such as powder generation, since this also leads to acceleration.

On the other hand, in the Cat-CVD method, since the plasma is not used, the above-mentioned problem of ion bombardment does not exist in principle, the generation of powder is extremely small, and the generation of atomic hydrogen is greatly promoted. Therefore, a crystalline Si film can be formed relatively easily at high speed, and further, there is no principle restriction on the enlargement of the area. Therefore, attention has been paid to the recent years (H. Matsumura, Jpn. J. Appl. . 37 (1998) 3175
-3187, REI Schropp et al, Technical digest of
11th PVSEC (1999) p. 929-930).

However, at present, there is an unavoidable problem that the temperature of the substrate rises due to radiation from the thermal catalyst, and it is not always easy to stably form a high-quality film. Also, SiH
_{Since the four} gases are directly decomposed by the thermal catalyst, generation of atomic Si is inevitable. This atomic Si is not preferable for the formation of a high quality Si film, and radicals such as SiH and SiH ₂ generated by the reaction of atomic Si with H and H _{2 in the} gas phase also form the high quality Si film. The formation of a high-quality crystalline Si film at a high speed has been very difficult because it is not preferable for the formation.

In order to solve the above problems, the present inventors have been studying the integration of the PECVD method and the Cat-CVD method for some time, and have already reported Japanese Patent Application Nos. 2000-130858 and 2
001-293030 and Japanese Patent Application No. 2002-67
No. 445, Cat-type Cat-
A PECVD process has been disclosed.

FIG. 11 shows a typical apparatus structure. FIG.
Reference numeral 700 denotes a shower head, 701 a source gas inlet, 702 a non-Si non-C gas inlet, 703 a source gas inlet, 704 a non-Si non-C gas inlet, 7
05 is a thermal catalyst, 706 is a heating power supply, 707 is a plasma space, 708 is a plasma generation electrode, 709 is a high-frequency power supply, 710 is a source gas outlet, 711 is a non-Si / non-C gas outlet, 712 Is a substrate for forming a film, 713 is a heater for heating the substrate, 714 is a vacuum pump for gas exhaustion, 7
Reference numeral 15 denotes a radiation blocking member.

In the Cat-PECVD method, a Si-based source gas and H ₂ gas are separated and introduced, and the H ₂ gas is heated and activated by a thermal catalyst 705 provided in a gas introduction path, and the Si-based gas is separated from the Si-based gas. Is used to form a film by being mixed in the plasma space 707, and a high-quality crystalline Si film having high crystallinity can be easily obtained even under high-speed film forming conditions. This degradation-activating amount of H ₂ by using a thermal catalyst in this way, it can be freely controlled independently of the decomposed and activating amount by plasma SiH _4, also SiH ₄ is activated only by the plasma Therefore, undesirable radical generation by the thermal catalyst 705 can be avoided, and the radiation blocking member 715 can be provided.
The silane generation reaction in the gaseous phase can be prevented by blocking the radiation that reaches directly, avoiding an undesired rise in the film formation surface temperature, and furthermore, by using the gas heating effect as a secondary effect using the thermal catalyst 705. Being suppressed (SiH ₂
Since the higher-order silane generation reaction due to the molecule insertion reaction is an exothermic reaction, an increase in the gas temperature due to gas heating has an effect of applying a brake to the higher-order silane generation reaction). Further, by using the shower head 700 and using a non-plate-like electrode (for example, an antenna electrode) as the plasma generation electrode 708 instead of the conventional plate-like electrode,
Even if a high-frequency power supply of 7 MHz or more was used, it had a capability of realizing uniform film thickness and uniform film quality in a large area. In addition, as a more specific form in this case, a method in which a non-planar electrode also serves as a shower head has been partially disclosed.
As described above, a satisfactory uniform film thickness distribution (within ± 15% as a guide) and a uniform film quality distribution (for example, within ± 15% as a crystallization rate distribution and within ± 10% as an efficiency characteristic distribution) in a 1 m square size are obtained. High-speed and high-quality film-forming conditions could be obtained.

However, even in the prior art by the present inventors having these remarkable effects, there is room for further improvement in the technique in which the non-plate-shaped electrode also serves as a shower head, and particularly with respect to the high productivity of the apparatus. Innovative technological development was desired.

[0017] The Technical digest of 11th PVSEC
(1999) p779 discloses a plasma CVD apparatus in which a thermal catalyst is disposed immediately after a hydrogen gas introduction port. Although the introduction ports of the hydrogen gas and the silane gas are different, the hydrogen gas and the silane gas do not pass through the shower electrode, and it is difficult to obtain a uniform film thickness distribution and film quality distribution over a large area. In addition, since the thermal catalyst is not isolated from the film forming space by the shower electrode, it is impossible to reduce the contact reaction with silane gas, which is undesirable in high-quality film forming, such as atomic Si and gas-phase reaction with it. In the same high-quality film formation as a generated molecule, generation of radicals such as SiH and SiH ₂ which are not preferable is inevitable. Further, the concept of the radiation blocking structure and the concept of the plasma generation frequency in the VHF band is not shown, and it is difficult to achieve high quality. In addition, it does not use an antenna electrode which is a core of the present invention described later.

Also, Technical digest of 16th EPSEC
(2000) p421 discloses a capacitively coupled RF plasma CVD apparatus in which a thermal catalyst is installed in a plasma space. It does not pass through the shower electrode. Further, since the thermal catalyst is installed in the plasma space, it is impossible to block radiation to the substrate. Also, there is no concept of an antenna electrode.

Japanese Patent No. 2692226 discloses a catalytic CVD method in which a radiation blocking member through which a gas can pass is provided between a catalyst and a substrate, but the raw material gas is not activated by the thermal catalyst. It does not separate the gas and introduce it, nor does it activate the source gas by plasma. Of course, there is no concept of an antenna electrode.

Japanese Patent Application Laid-Open No. 10-310867 discloses a thin film forming apparatus provided with a catalyst electrode between a plasma generating electrode and a gas inlet, but separates and introduces a source gas. It does not have a radiation blocking structure. Also, there is no concept of an antenna electrode.

Japanese Patent Application Laid-Open No. 11-54441 discloses that a raw material gas is supplied into a container in which a thermal catalyst is disposed, and the inside of the container is isolated from a substrate. CVD supplied to substrate
Although an apparatus is disclosed, it does not separate and introduce a raw material gas, and does not relate to a PECVD method. Also, there is no concept of an antenna electrode.

Further, Japanese Patent No. 199,526 discloses that
Although a method of forming a film by introducing a source gas and a heating gas for decomposing the source gas is disclosed, the method does not use a shower head and does not have a radiation blocking structure. Also, there is no concept of an antenna electrode.

Also, Japanese Patent No. 19945527 discloses that
Although a method of forming a film by thermally decomposing a raw material gas is disclosed, the method is not a method that does not thermally decompose the raw material gas and does not have a radiation blocking structure. Further, neither a plasma nor a shower head is used.
Of course, there is no concept of an antenna electrode.

Japanese Patent No. 1927388 discloses that
A method of activating a gas containing hydrogen by providing a mesh-shaped activation means made of tungsten in a film forming space and activating a gas containing hydrogen is disclosed, but not a method of separating and introducing a raw material gas without thermal decomposition. Neither does it have a radiation blocking structure. Also, there is no concept of an antenna electrode.

[0025] Also, Japanese Patent No. 2547741 discloses that
A structure in which one transport pipe has the other inside it,
Although a method for separating and introducing iH ₄ and H ₂ is disclosed,
It does not use a shower head and does not have a radiation blocking structure. Also, there is no concept of an antenna electrode.

Further, Japanese Patent No. 2927944 discloses that
Activate the hydrogen gas in a space different from the film formation space, mix it with the source gas, and contact it to form a plasma region,
A method of performing film deposition by intermittently and periodically exposing the substrate to plasma by activating the hydrogen gas periodically is disclosed. However, the method does not use a shower head, Nor does it have a blocking structure.
Also, there is no concept of an antenna electrode.

Japanese Patent Application Laid-Open No. 2000-114256 discloses a method in which a raw material gas is decomposed by the action of a catalyst and plasma-treated to form a film. Nor does it use a shower head, nor does it have a radiation blocking structure. Also, there is no concept of an antenna electrode.

Japanese Patent Application Laid-Open No. 2000-331942 discloses a method of forming a film by using an apparatus having a surface reaction mechanism provided near a substrate from a plasma generating section to a substrate surface. It does not separate and introduce the gas without thermal decomposition and does not use a shower head. Further, since the thermal catalyst is between the plasma and the substrate, it is impossible to block radiation to the substrate. Also, there is no concept of an antenna electrode.

Japanese Patent Application Laid-Open No. 2000-323421 discloses that SiH ₄ and H ₂ are separately introduced, SiH ₄ gas is activated by plasma to irradiate the substrate with ions and radicals, and H ₂ gas is introduced by gas introduction. A method of irradiating a substrate with activation by a heating catalyst provided in a mouth is disclosed, but it does not use a shower head and does not have a radiation blocking structure. Also, there is no concept of an antenna electrode.

In Japanese Patent Application Laid-Open No. Hei 9-137274, SiH ₄ and H ₂ are separately introduced into a plasma space, and H ₂
Discloses a method of activating with heat or plasma in the introduction process, but not using a shower head,
Nor does it have a radiation blocking structure. Also, there is no concept of an antenna electrode.

Japanese Unexamined Patent Publication No. Hei 4-236781 discloses an antenna electrode type PECVD apparatus excellent in uniform large-area film formation using a ladder-like planar coil (ladder) electrode. It does not use a medium to heat and activate the gas.

Japanese Patent Application Laid-Open No. 2001-295052 discloses an AM-modulated VHF high frequency (20 to 600
Although an antenna electrode type PECVD apparatus capable of forming a large-area uniform film thickness by supplying a microwave (MHz to microwave) is disclosed, it does not heat and activate a gas using a thermal catalyst.

Further, Japanese Patent Application Laid-Open No. 7-41950 discloses that
A method of preliminarily heating a hardly decomposable gas with a gas heater and improving the decomposability in plasma to obtain a high-quality film has been disclosed. Rather than installing a thermal catalyst in the
In addition, activation (decomposition) does not lead to activation only by heating the gas. In addition, SiH ₄ and H ₂ are separated and introduced, and H ₂
It does not heat and activate only the thermal catalyst.

Japanese Patent Application Laid-Open No. Hei 6-283436 describes a method for realizing high-speed film formation by heating and introducing a reactive gas. It does not place a thermal catalyst in the inside, nor does it lead to activation (decomposition) only by heating the gas. Further, the method does not separate and introduce SiH ₄ and H ₂ and heat and activate only H ₂ with a thermal catalyst.

Japanese Patent Application Laid-Open No. 5-283344 discloses that a heater for independently controlling the temperature of a wire is incorporated into the wire of the ladder-shaped planar coil electrode to control the reaction gas pressure distribution in the reaction vessel. Although a method for achieving uniform and homogeneous film formation is described, it does not use a thermal catalyst, and therefore does not place a thermal catalyst in an antenna electrode, and activates only by heating a gas ( Decomposition). Further, the gas is not separated and introduced depending on the type of gas.

The present invention has been made in view of such a background, and is intended to produce Si-based films or C-based films at high speed and with high quality and with uniform film thickness and uniform film quality over a large area. It is an object to provide a Cat-PECVD method which can be formed into a film and which can realize extremely high productivity, a film formed using the method, and a device manufactured using the film.

[0037]

The Cat-PEC of the present invention
The VD method includes a non-Si gas containing a source gas containing a gas containing Si and / or C in a molecular formula, and a gas containing no Si and C in a molecular formula heated by a thermal catalyst disposed in a gas introduction path. The non-C-based gas is separated from a plurality of gas outlets provided in the antenna electrode through a hollow portion of an antenna electrode having a hollow structure installed in a film forming space in a state where the non-C-based gas is separated from each other. The gas spouted into the space, spouted into the film forming space and mixed therewith is decomposed and activated by the plasma generated by the antenna electrode connected to the high-frequency power supply, and faces the antenna electrode in the film forming space. The film is deposited on the substrate arranged in the manner described above.

Further, in particular, the antenna electrode is rod-shaped or U-shaped, the thermal catalyst is disposed in a hollow portion of the antenna electrode, and the plurality of antenna electrodes are arranged in parallel to form an array. Forming the antenna electrode unit, separating and introducing gases are ejected from different antenna electrodes, and the film is introduced into the source gas introduction path and / or the non-Si non-C-based gas introduction path. And introducing a gas for doping therein.

Further, the film of the present invention is formed of the above Cat-PECV.
It is characterized by being formed by the D method. In particular, in this film, the source gas contains a gas containing Si in a molecular formula, but does not contain a gas containing C in a molecular formula, and the non-Si non-C gas contains H _2. The Si-based film is a hydrogenated amorphous Si film, and the hydrogen concentration in the film is 15 atomic%.
The following, the Si-based film is a crystalline Si film,
The hydrogen concentration in the film is 10 atomic% or less, the raw material gas contains a gas containing Si in a molecular formula and a gas containing C in a molecular formula, and the non-Si non-C-based gas contains H _2. The raw material gas contains a gas containing Si in a molecular formula, the non-Si non-C gas contains H ₂ , and the raw material gas or A Si-N-based film formed by including a gas containing N in a molecular formula in at least one of a non-Si / non-C-based gas; and the raw material-based gas contains a gas containing Si in a molecular formula. The non-Si non-C-based gas is a Si—O-based film formed by including a gas containing O in a molecular formula, and the raw material gas is a gas containing Si in a molecular formula and a gas containing Ge. And the non-S
i The non-C-based gas is a Si-Ge-based film formed by including H ₂ , and the raw material-based gas includes a gas containing C in a molecular formula, and the non-Si non-C-based gas Is a C-based film formed by containing H ₂ .

Further, a thin-film device of the present invention is provided with the above-mentioned film. In particular, the thin film device is a photoelectric conversion device, a photoreceptor device, or a display device, and the base is a flat plate, a cylinder, or a film.

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings schematically showing the embodiments. FIG. 1 is an overall view showing an example of an apparatus for realizing the Cat-PECVD method of the present invention, in which a thermal catalyst is incorporated when the film-forming surface of a flat substrate is oriented in a direction perpendicular to the plane of the paper. It is sectional drawing in the position of an antenna electrode. FIG.
It is sectional drawing at the time of installing a heater in the inner wall of a film-forming room (chamber). FIG. 3 shows an example in which the antenna electrodes are arranged in an array, and is a cross-sectional view when the film-forming surface of the substrate is oriented in a direction parallel to the paper surface. Only a part of the unit is shown, and details of the end structure of the antenna electrode are omitted: refer to FIGS. FIG. 4 is a cross-sectional view of the array-shaped antenna electrode as viewed from the center axis direction. FIG.
FIG. 2 is a sectional view showing a detailed structure of an antenna electrode. FIG.
FIG. 3 is a perspective view showing a three-dimensional structure of an antenna electrode. FIG.
FIG. 3 is a cross-sectional view illustrating a structure of an antenna electrode including a plurality of thermal catalysts.

In these figures, reference numeral 101 denotes an inlet for a raw material gas containing a gas containing Si and / or C in a molecular formula;
102 is a non-S composed of a gas not containing Si and C in the molecular formula.
i, a non-C-based gas inlet; 103, a thermal catalyst; 104, a power supply for heating the thermal catalyst 103;
a is an antenna electrode with a built-in thermal catalyst, 106b is an antenna electrode without a built-in thermal catalyst, 107a and 107
b is a high frequency power supply, 108a and 108c are phase converters, 108b and 108d are power distributors, 109, 1
Reference numerals 09a and 109b denote bases for forming a film, 110 denotes a heater for heating the base, 111a denotes a gas ejection port provided in the antenna electrode 106a with a built-in thermal catalyst, and 111b denotes a gas outlet provided in the antenna electrode 106b without a built-in thermal catalyst. Gas injection port, 112 is an insulating member for electrical insulation, 113 is a chamber (film forming chamber) constituting a film forming space, 114a and 11
4b is a hollow portion provided inside the antenna electrode, 115
Is an inner wall heater provided on the inner wall of the chamber, 11
6 is a selection switch for the thermal catalyst.

As described above, the Cat-PECVD of the present invention
The method comprises the steps of: a raw material gas containing a gas containing Si and / or C in a molecular formula;
The antenna electrodes (106b, 106a) having a hollow structure and installed in a film forming space in a state where a non-Si non-C-based gas composed of a gas not containing Si and C in a molecular formula heated by 03 are separated from each other. ) Hollow section (114b, 1)
14a), the gas spouted from the plurality of gas spouts provided in the antenna electrode into the film forming space, and the gas spouted into the film forming space and mixed therewith is supplied to the high frequency power source (107a, 10a).
7b) is decomposed and activated by the plasma generated by the antenna electrode connected to 7b), and is disposed in the film forming space so as to face the antenna electrode.
At 09 a film is deposited. And, as described later, the plurality of antenna electrodes are arranged in parallel to form an array-shaped antenna electrode unit, and high-frequency power from the high-frequency power source is applied to each antenna electrode of the array-shaped antenna electrode unit. It is characterized by being distributed and introduced.

Although not shown, the chamber 11
3 is evacuated by a vacuum pump. At this time, it is desirable to use a dry pump such as a turbo-molecular pump in order to suppress the contamination of impurities from the exhaust system into the film formed on the substrate. At this time, the ultimate degree of vacuum is at least 1 × 10 ⁻³ Pa or less and 1 × 1 ⁻³ Pa or less.
It is more preferable that the pressure be 0 ^-4 Pa or less. The pressure during film formation is 1
The range is about 0 to 1000 Pa. The temperature of the substrate 109 by the substrate heating heater 110 is 100 to 40.
The temperature condition is 0 ° C., preferably 150 to 350 ° C.

Hereinafter, each part will be described in detail. = Electrode Shape = First, as the shape of the antenna electrode, a shape such as a rod shape or a U shape can be selected. Specifically, the rod-shaped one is the simplest one. For example, JP-A-1-47875,
JP-A-1-230782, JP-A-2001-274
No. 101 publication. The U-shape is disclosed in JP-A-4-21781.

Here, the reason why the antenna type electrode is used instead of the conventional flat type electrode is as follows. In general,
The relationship between the frequency f of the high frequency power supply and the wavelength λ is given by λ = v / f in the plasma. Here, v is the propagation speed of the electromagnetic wave in the plasma, which is smaller than the speed c (light speed) of the electromagnetic wave in a vacuum.
It is as follows. On the other hand, assuming that the length L of one side of the square electrode is a typical characteristic length as the size of the plasma generation electrode, λ≫
When L is used, an electromagnetic wave interference effect does not occur and uniform plasma is generated, so that a film having a uniform thickness and a uniform film quality can be formed. For example, when f = 13.5 MHz, λ is about 22 m at the maximum, and it can be seen that the interference effect is not a problem with a 1 m square plasma generating electrode.

However, when the frequency f of the high-frequency power supply is increased and λ / 4 becomes a value of about L or less, the interference effect cannot be ignored. For example, when f = 60 MHz, λ / 4 becomes 1.25 m at the maximum, and an interference effect occurs in a simple plate-shaped plasma generation electrode having a 1 m square size, and a uniform electromagnetic field distribution, that is, a uniform plasma generation is generated. Can not be expected.

For this reason, in the case of forming a large-area film having a size of about 1 m square or more in a region where the frequency of the high-frequency power supply is equal to or higher than the VHF band, an antenna-type electrode is used instead of a flat-type plasma generation electrode, and Technology development for uniformizing plasma generation by introducing a control technology and the like is progressing, and this technology can also be used in the present Cat-PECVD method.

The cross-sectional shape parallel to the direction perpendicular to the long axis direction of the antenna electrode may be generally circular or rectangular. However, when more uniform film forming characteristics are particularly required, the surface is more uniform. It is preferable to use a rectangular shape capable of realizing a simple plasma generation. = Installation position of the thermal catalyst body = Next, the installation position of the thermal catalyst body 103 is most preferably shown in FIGS. 1, 2, 3, 4, 5, 6, and 7. This is the case where the antenna electrode is installed inside (hollow portion) of the antenna electrode having the hollow structure. By placing the thermal catalyst inside the antenna electrode, the heated and activated non-Si non-C-based gas enters the plasma space generated outside the antenna without excessively impairing its temperature and activity. Since it is fed, its effect on film formation can be sufficiently maintained. H _2, for example, non-Si non-C-based gas
In the case of using SiH ₄ as a raw material gas, a low hydrogen dilution rate (low H ₂
/ SiH ₄ ratio) and crystalline Si under low-frequency power conditions
The effect of easily forming a film or forming a hydrogenated amorphous Si film having a low hydrogen concentration in the film, which was also difficult without using a thermal catalyst, is obtained.

As described above, the position of the thermal catalyst 103 is most preferably located inside the hollow antenna electrode. However, even when the thermal catalyst 103 is disposed in the gas path on the upstream side of the hollow antenna, the above-described effects can be obtained. If it is particularly difficult to install the thermal catalyst inside the hollow antenna electrode, the thermal catalyst can be installed in the gas path on the upstream side of the hollow antenna. However, in any case, it is still the most desirable to dispose the thermal catalyst in the antenna electrode in order to maximize the effects of the present invention. = Arraying of Antenna Electrodes = Next, the way of arranging the antenna electrodes is as follows. The base 109 is a plate material or a film material having a certain area, for example, a substrate such as a solar cell. As shown in FIGS. 3 and 4, a plurality of antenna electrodes are desirably arranged in parallel and arranged in an array to form an array antenna electrode unit.
Thereby, a film can be formed uniformly and over a large area. = Gas separation and introduction method = Next, a method for separating and introducing a non-Si non-C-based gas and a raw material-based gas is the simplest method. As shown in FIG. This is the case. At this time, the thermal catalyst 103 is placed inside the antenna electrode 106a into which the non-Si non-C-based gas is introduced. Here, if the distance between the antenna electrodes cannot be sufficiently reduced, and there is a possibility that the mixing of the non-Si non-C-based gas and the raw material-based gas in the plasma may be insufficient, a single antenna electrode may be used. A plurality of independent hollow spaces may be formed so that the non-Si non-C-based gas and the raw material-based gas are simultaneously ejected from one antenna electrode through different hollow spaces (not shown). Also at this time, the thermal catalyst 103 is provided in the introduction path of the non-Si non-C-based gas.

The reason why the raw material gas and the non-Si non-C-based gas are separately introduced is that it is desired to heat only the non-Si non-C-based gas with the thermal catalyst. That is, if the raw material gas and the non-Si non-C gas are mixed and introduced, not only the non-Si non-C gas but also the raw material gas is heated by the thermal catalyst disposed in the introduction path. Will end up doing
When the temperature of the thermal catalyst is equal to or higher than the decomposition temperature of the raw material gas, the raw material gas is decomposed and activated, and a film is formed on the gas introduction path, and before the raw material gas reaches the film forming space. This is because it is significantly consumed. = Gas Outlet Position = Next, as for the gas outlet position, in the case of the antenna electrode 106a in which the thermal catalyst 103 is installed, as shown in FIG. Catalyst 1
03 from the substrate 109a or 109
It is desirable to be arranged so as not to reach b directly. Thus, an undesired increase in the film forming surface temperature due to the radiation generated from the thermal catalyst can be avoided, and stable control of the film quality can be realized. In addition, in the case of the antenna electrode 106b in which the thermal catalyst is not installed inside, the gas outlet may be at an arbitrary position. = Arrangement of Array-shaped Antenna Electrode Unit = Next, it is desirable that the array-shaped antenna electrode unit is vertically arranged such that its array surface is parallel to the direction of gravity. By doing so, it is possible to very effectively prevent the powder from dropping and adhering to the base 109 during film formation on both sides of the array-shaped antenna electrode unit as described later. Further, when a glass substrate or the like is used as the base 109, for example, the glass substrate can be transported in a vertical type, so that there is an advantage that handling becomes very easy without causing a problem of bending of the glass substrate. Of course, in this case, there is an advantage that the problem of bending of the array antenna electrode unit itself does not occur.

As described above, it is desirable that the array-shaped antenna electrode unit is arranged vertically so that its array surface is parallel to the direction of gravity. The horizontal arrangement so as to be perpendicular to the direction is not particularly limited, and the latter horizontal arrangement is adopted if the problem of the deflection of the array electrodes and the base and the fall-off of the powder can be almost ignored. No problem. = Substrate Arrangement = Next, it is desirable that the substrates 109 are arranged on both sides of the array-shaped antenna electrode unit (see FIGS. 1 and 4). This enables simultaneous film formation on both sides of the array-shaped antenna electrode unit, and can double the productivity of the apparatus. = Substrate Heater Arrangement = Next, as shown in FIG.
It is desirable to arrange on both sides of the array-shaped antenna electrode unit with the substrate interposed therebetween. That is, it is preferable that a substrate heating heater is disposed on the surface of the substrate opposite to the surface facing the array antenna electrode unit. This makes it possible to control the substrate film forming surface temperature during film formation, and it becomes easier to realize high quality film formation. = Number of Array-shaped Antenna Electrode Units and Array = Next, it is desirable that a plurality of sets of array-shaped antenna electrode units are arranged in parallel in one film forming chamber (FIG.
An example in which three array-shaped antenna electrode units are arranged is shown). By doing so, simultaneous film formation by a plurality of array-shaped antenna electrode units becomes possible. Considering the simultaneous double-sided film formation with one array-shaped antenna electrode unit, for example, two sets of array-shaped antenna electrode units are arranged in parallel. If this is done, simultaneous film deposition on four sides is possible, and if three sets are arranged in parallel, simultaneous film formation on six sides is shown (FIG. 1 shows this case). As described above, if the number of arrayed antenna electrode units arranged in parallel is increased, the productivity as a film forming apparatus can be increased to several times or more at once. This is impossible at all with a conventional parallel plate type PECVD apparatus. = Power Supply Method = Next, as a method of supplying power to the antenna electrode 106a or 106b, for example, as shown in FIG. 3, high-frequency power from the high-frequency power supply 107a or 107b is distributed by the power distributor 108b or 108d to transmit power. I do. Here, the number of high-frequency power sources and the number of distributions do not necessarily have to match, and it is usually effective to reduce equipment costs if a larger number of high-frequency power sources are used to realize more power distribution. Here, with one high-frequency power supply,
When all necessary high-frequency power cannot be distributed and supplied, a plurality of high-frequency power supplies can be prepared and distributed and supplied as needed. = Phase Control = Next, in order to prevent non-uniform distribution of plasma due to unnecessary interference effects (strengthening and destruction), it is desirable that the phase of the high-frequency power is different at least between adjacent electrodes. This is the phase converter 108a or 1
08c, but the same effect can be obtained by arranging the feeding points to the adjacent antenna electrodes of the array-shaped antenna electrode unit so as to be located in opposite directions, for example, as shown in FIG. Can be realized, and more uniform large-area plasma can be generated by using both of them. = High-frequency power supply method = Another method for making it easier to achieve uniform film thickness and uniform film quality over a large area is the antenna electrode 10.
There is a method of superimposing a plurality of plasmas having different spatial density distributions by superposing and supplying a plurality of high-frequency powers having different frequencies to 6a and 106b. As a result, the plasma density distribution can be made more uniform, so that a large-area and uniform film can be formed on the substrate.

As another method, there is a method in which high-frequency power having a different frequency is supplied to each adjacent antenna electrode. This may be achieved, for example, by making the frequencies of the high frequency power supplies 107a and 107b different in FIG. In this case, the plasma density distribution can be made more uniform by the electromagnetic interaction between the adjacent electrodes, so that a large-area uniform film can be formed on the substrate.

As still another method, the high-frequency power frequency is fluctuated / modulated with time, the spatial density distribution of plasma is fluctuated with time, and the time average is obtained, resulting in uniform film formation. There is a way to

Further, if high-frequency power is intermittently supplied to the antenna electrodes 106a and 106b by, for example, pulse-modulating the plasma, the generation and growth of powder can be suppressed as compared with the case of continuous plasma generation. In some cases, it is effective for improving the film quality. = High-frequency power supply frequency = Next, in the Cat-PECVD method and apparatus of the present invention,
The antenna electrodes 106a and 106b for generating plasma are connected to high-frequency power sources 107a and 107b, and the frequency of the high-frequency power sources 107a and 107b is 1
It is characterized by a frequency of 3.56 MHz or higher, but the effect of the present invention, that is, the effect on large-area uniform film thickness / homogeneous film formation is remarkably exhibited, particularly in a high frequency region of 27 MHz or higher (so-called VHF band or higher). It is.

That is, in the conventional plate-shaped electrode, as described above, a large-area film having a uniform film thickness of about 1 m square size and uniform film quality can be realized without relatively difficult operation up to about 27 MHz. However, according to the present invention, even in a high-frequency region of 27 MHz or more, a large-area uniform film thickness / homogeneous film formation is remarkably superior to the conventional technology even in a high-frequency region of 27 MHz or more. Characteristics are obtained.

As the high frequency frequency in the VHF band, an arbitrary value can be selected as a continuous amount, and it is desirable to select an optimum frequency according to the electrode size and shape, but usually, it is often used industrially. 40MHz, 60MHz,
It is sufficient to use a frequency such as 80 MHz or 100 MHz.

Here, the high frequency power supplies 107a and 107
Since the higher the frequency of b, the higher the electron density in the plasma, the higher the activation rate of decomposition of the raw material gas and the higher the film forming speed. Further, as a non-Si non-C-based gas, H
_{When two} gases are used, the generation rate of atomic hydrogen is also increased, so that the crystallization promoting effect is more remarkably obtained. Therefore, a crystalline Si film can be obtained even under high-speed film forming conditions.

Further, in the present invention, non-S
Since activation of the non-C-based gas can be further promoted, when H ₂ gas is used as the non-Si non-C-based gas, the crystallization promoting effect is further increased in addition to the above-described effect of VHF itself. However, a high-quality crystalline Si film can be obtained even under further high-speed film forming conditions. In particular, when a hydrogenated amorphous Si film is formed, a film having a lower hydrogen concentration can be formed, and a hydrogenated amorphous Si film having more excellent light stability than the conventional PECVD method alone can be obtained.

The frequency of the high frequency power supply is 100 MHz.
It is not necessary to limit to a VHF band up to about z, and it is possible to use a UHF band having a higher frequency or a frequency in a microwave region. = Thermal catalyst body = Next, the thermal catalyst body 103 is made of a metal material at least on its surface in order to make it function as a thermal catalyst body by applying an electric current thereto and heating and increasing the temperature by the Joule heat.
This metal material is more preferably a refractory metal material T
It is desirable to use a metal material containing at least one of a, W, Re, Os, Ir, Nb, Mo, Ru, and Pt as a main component. Further, as the thermal catalyst body 103, usually, a metal material such as described above in the form of a wire is often used, but not particularly limited to the wire shape, and a plate-like or mesh-like material may be used. it can. If the metal material as the thermal catalyst material contains impurities that are not preferable for film formation, the thermal catalyst 1
Preliminary heating for several minutes or more at a temperature higher than the heating temperature at the time of film formation before using 03 for film formation is effective in reducing impurities. = Power supply for heating the thermal catalyst = As the power supply 104 for heating the thermal catalyst 103, it is usually convenient to use a DC power supply, but using a low frequency AC power supply that does not generate plasma. No problem. When a DC power supply is used, a non-Si
DC power may be intermittently supplied to the thermal catalyst 103 in order to control the degree of heating or decomposition / activation of the non-C-based gas. = Activation of non-Si non-C-based gas = Next, the non-Si non-C-based gas is heated by the thermal catalyst 103 and guided to the plasma space 105, but partly decomposed and activated by the thermal catalyst 103. And the degree is proportional to the temperature of the thermal catalyst. For example, in the case of H ₂ gas, the generation of atomic hydrogen by the decomposition reaction becomes remarkable when the temperature of the thermal catalyst exceeds about 1000 ° C., depending on the pressure. This atomic hydrogen acts very effectively to promote crystallization of the Si film as described above. Even if the temperature of the thermal catalyst is about 1000 ° C. or less, the generation of atomic hydrogen is not so remarkable, and the temperature condition in which the crystallization promoting effect is not so expected, the secondary effect of using the thermal catalyst is obtained. As a result, the higher-order silane generation reaction is suppressed by the gas heating effect, so that it is also effective for forming a high-quality hydrogenated amorphous silicon film. However, it is desirable that the temperature of the thermal catalyst be at least 100 ° C. or more, more preferably 200 ° C. or more, in order to obtain the above effect. By setting the temperature to 200 ° C. or higher, the effect of gas heating can be more remarkably obtained. Note that the maximum temperature of the thermal catalyst body is 200
0 ° C. or lower, more preferably 1900 ° C. or lower. 19
If the temperature exceeds 00 ° C., problems such as degassing of impurities from the catalyst and peripheral members and evaporation of the material itself of the catalyst begin to occur. If the temperature exceeds 2000 ° C., the degassing and the evaporation become remarkable. = Activation Amount Control Method = Here, a method other than controlling the degree of heating or decomposition / activation of the non-Si non-C-based gas represented by H ₂ by the above-described temperature of the thermal catalyst is realized. As a method,
There are the following.

The first method is to control the surface area of the thermal catalyst 103. According to this, without lowering the temperature of the thermal catalyst 103, the non-S
The degree of heating or decomposition and activation of the i non-C-based gas can be controlled. For example, when a linear catalyst is used as the thermal catalyst 103, the thermal catalyst 1 can be selected by selecting its wire length and diameter, and furthermore, by selecting the number to be installed in one antenna electrode.
03 can be controlled. In particular, as shown in FIG. 7, when a plurality of thermal catalysts 103 are provided in one antenna electrode, if these can be heated independently, the thermal catalysts 103 to be heated as needed are required.
The degree of heating or decomposition / activation of the non-Si non-C-based gas can be changed in a stepwise manner by determining the number.

The second method is to heat the thermal catalyst 103 intermittently or periodically. Specifically, if the power of the heating power supply 104 is provided intermittently, for example, in a pulsed manner, or if a low-frequency AC power supply is used, the heating of the thermal catalyst 103 can be performed periodically. Thereby, the non-Si non-C-based gas and the thermal catalyst 10 per unit time
3 can be continuously controlled, so that the degree of heating or decomposition / activation of the non-Si non-C-based gas can be continuously controlled.

The third method is to use a non-Si non-C gas outlet 1
The diameter of the gas inlet 11a and the diameter of the raw material gas outlet 111b are separately designed and adjusted.
The total number of a and the total number of the raw material gas ejection ports 111b are separately designed and adjusted. The reduction in the diameter or the total number of ports in the non-Si non-C-based gas ejection port 111a is as follows.
The amount of the heated or decomposed and activated non-Si non-C-based gas ejected into the plasma space 105 is reduced, and the increase in the diameter or the total number of ports in the non-Si non-C-based gas ejection port 111b is caused by the heating or decomposition or activation. Activated non-Si non-C
The amount of system gas ejected into the plasma space 105 can be increased.

The fourth method is to add a non-Si non-C-based gas introduction path (not shown) in which a thermal catalyst is not provided to the gas introduction path, and to add a non-Si non-C-based gas through the thermal catalyst 103. The present invention enables independent control of the gas flow rate and the flow rate of the non-Si non-C-based gas that does not pass through the thermal catalyst. That is, there are a plurality of non-Si non-C-based gas introduction paths, and at least one non-Si non-C-based gas is introduced into the plasma space without being heated by the thermal catalyst. As a result, the heated or decomposed and activated non-Si non-C-based gas and the non-heated non-Si non-C-based gas can be mixed at an arbitrary gas flow ratio, and are released into the plasma space 105. It is possible to continuously change the density of the heated or decomposed and activated non-Si non-C-based gas. Here, the non-Si non-C-based gas introduction path that is not heated may be merged with the raw material-based gas introduction path, and such a merger simplifies the introduction structure. = Gas path material = Next, at least a part of the surface of at least one of the inner wall of the gas pipe and the inner wall of the hollow antenna electrode in the non-Si non-C-based gas introduction path includes at least one of Ni, Pd, and Pt. It is desirable to be made of a material that contains. Since these metal elements have a catalytic action to promote the dissociation of gas molecules such as H ₂ , the probability that the decomposed and activated non-Si non-C-based gas is recombined and deactivated on the member surface Can be lowered. = Gas Heating = Next, it is desirable to arrange a thermal catalyst (not shown) also in the raw material gas introduction path in order to promote the gas heating effect. However, the temperature of the thermal catalyst is controlled to be lower than the temperature at which the raw material gas is decomposed so that the raw material gas is not decomposed by the thermal catalyst. For example, when using SiH ₄ as a source gas, the temperature is set to 500 ° C. or lower, preferably 400 ° C. or lower.

As another method for promoting the gas heating effect, there is a method of installing a heater on the wall surface of the film forming chamber. That is, in the conventional method in which the inner wall surface of the film forming chamber is not particularly heated, a higher silane generation reaction (exothermic reaction) easily occurs on the inner wall surface of the film forming chamber having a low temperature, and this is an important factor of the deterioration of the film quality. In contrast to the source of powder generation, this method actively heats the inner wall of the film-forming chamber, which suppresses the exothermic reaction of higher silane generation and reduces the amount of powder generated. it can. Specifically, as shown in FIG. 2, if a heater is installed on the wall surface of the film forming chamber, the wall surface of the film forming chamber can be heated. Here, when the raw material gas contains a gas containing Si in a molecular formula, the temperature of the heater is set to 500 ° C. or lower, preferably 400 ° C. or lower. Thereby, the thermal CVD reaction (film formation reaction) on the heater surface is sufficiently suppressed,
Waste of the source gas in this portion can be suppressed. = Method of Introducing Doping Gas = Next, when supplying a doping gas, the doping gas can be introduced into the source gas introduction path and / or the non-Si non-C-based gas introduction path. At this time, B ₂ H ₆ or the like can be used as the p-type doping gas, and PH ₃ or the like can be used as the n-type doping gas. = Electric Circuit = It is desirable to install a pass capacitor (not shown) as high-frequency blocking means in the circuit of the catalyst body heating power supply 104. Thus, the entry of high-frequency components from the high-frequency power supply can be prevented, and stable film formation can be realized more reliably. = Base Shape = As the base 109, for example, in the case of a device such as a solar cell, a flat shape such as a glass substrate or a film shape such as a metal material or a resin material can be used. In the case of such a device, a non-flat plate such as a cylindrical one can be used. = Apparatus (see FIG. 8) = A film processing system for realizing the Cat-PECVD method of the present invention is a film processing system including a plurality of vacuum chambers having at least one film forming chamber capable of realizing the above-described method.

The plurality of vacuum chambers include at least a p-type film forming chamber, an i-type film forming chamber, and an n-type film forming chamber. The film forming chamber for use is preferably a film forming chamber capable of realizing the Cat-PECVD method of the present invention.

It is preferable that at least one of the plurality of vacuum chambers is a film forming chamber capable of realizing Cat-CVD. This enables, for example, a high-speed and high-quality hydrogenated amorphous silicon film to be formed by a Cat-CVD method. For example, a hydrogenated amorphous silicon film can be used as a photoactive layer of a top cell of a tandem solar cell. For example, the degree of freedom in combination when forming a multilayer film can be increased. It is known that a hydrogenated amorphous silicon film formed by the Cat-CVD method can have a lower hydrogen concentration than that formed by the PECVD method. Therefore, it is possible to realize a smaller optical bandgap characteristic having more excellent light absorption characteristics. it can. Another advantage is that the photodegradation characteristic, which has been a long-standing problem of hydrogenated amorphous silicon films, can be suppressed.

It is desirable that at least one of the plurality of vacuum chambers is a film forming chamber capable of realizing the PECVD method. This makes it possible, for example, to achieve film deposition on a film surface that is vulnerable to the reducing action of atomic hydrogen such as an oxide transparent conductive film under conditions in which this reducing action is suppressed as much as possible.
The degree of freedom in combination when forming a multilayer film can be increased.

It is desirable that the plurality of vacuum chambers include at least a front chamber for the purpose of keeping the film forming chamber from opening to the atmosphere. Further, if the plurality of vacuum chambers include at least the front chamber and the rear chamber, production may be performed. It is more desirable in terms of improving the performance. Also, it is desirable that the plurality of vacuum chambers include at least a heating chamber in order to improve productivity.

In the method of arranging the plurality of vacuum chambers, the plurality of vacuum chambers may be connected and arranged in a linear manner, or the plurality of vacuum chambers may be connected to at least one existing core chamber. Can also be placed.

Here, it is desirable that the film forming chamber is of a vertical type for processing a substrate such as a glass substrate in a vertical type. By using the vertical type, it becomes less susceptible to the drop adhesion of foreign matter such as powder, which is a problem in the horizontal deposit-down system, and the uneven temperature on the base film formation surface due to the warpage of the substrate, which is a problem in the horizontal deposit-up system. Distribution is less likely to occur. However, as long as these problems do not actually cause a problem, a horizontal type may be used. = Film = According to the Cat-PECVD method of the present invention, it is possible to form a high-speed and high-quality film with high uniformity in both film thickness and film quality over a large area. The effect on film formation is described in Japanese Patent Application No.
001-293031 and Japanese Patent Application No. 2002-38686), and specifically, the effect is particularly remarkable for the Si-based film or the C-based film described below.

In the first example, the raw material gas contains Si as a molecular formula.
Is contained, but a gas containing C in the molecular formula is not contained. The non-Si non-C-based gas is a Si-based film formed by containing H ₂ . Specifically, for example, when SiH ₄ is used as a source gas and H ₂ is used as a non-Si non-C gas, a high-quality hydrogenated amorphous silicon film or a high-quality crystalline silicon film is used for the reasons described above. Can be formed at high speed and with high uniformity of film thickness and film quality over a large area.

According to the method of the present invention, the hydrogen concentration in the hydrogenated amorphous silicon film can be reduced to 15 atomic% or less. More preferably, it can be set to 10 atomic% or less, further preferably 5 atomic% or less, whereby the problem of photodegradation of the hydrogenated amorphous silicon film, which has been a long-standing problem, can be significantly reduced. When used in a battery, high stabilization efficiency can be obtained.

Further, according to the method of the present invention, the hydrogen concentration in the crystalline silicon film can be reduced to 10 atomic% or less. More preferably 5 atomic% or less, and even more preferably 3.5 atomic% or less, whereby the deterioration with time of the characteristics caused by the post-oxidation phenomenon at the crystal grain boundaries described in the embodiment of the solar cell described later. Can be reduced. That is, by setting the hydrogen in the film to 5 atomic% or less, the temporal deterioration rate can be reduced to about several percent or less, and by setting the hydrogen concentration in the film to 3.5 atomic% or less, the temporal deterioration rate can be made almost zero.

In the second example, the raw material gas contains Si as a molecular formula.
And a gas containing C in the molecular formula, and H ₂ is contained in the non-Si non-C-based gas.
It is an iC-based film. Specifically, for example, if SiH ₄ and CH ₄ are used as the source gas and H ₂ is used as the non-Si non-C gas, a high-quality hydrogenated amorphous silicon carbide film or a high-quality A crystalline silicon carbide film can be formed at high speed and with high uniformity of film thickness and film quality over a large area. In a third example, the raw material gas contains a gas containing Si in a molecular formula,
The non-Si non-C-based gas contains H ₂ , and the gas containing N in the molecular formula is Si—N formed by being included in at least one of the raw material-based gas and the non-Si non-C-based gas.
It is a system membrane. Specifically, for example, SiH is used as a raw material gas.
₄ , H ₂ as a non-Si non-C-based gas, and NH ₃ as a N-containing gas, a high-quality hydrogenated amorphous silicon nitride film or a high-quality crystalline silicon nitride film can be formed for the reasons described above. It can be formed at high speed and with high uniformity of film thickness and film quality over a large area.

The fourth example is that the raw material gas has a molecular formula of Si.
Is contained in the non-Si non-C-based gas.
Formed by containing a gas containing
It is a system membrane. Specifically, for example, SiH is used as a raw material gas.
_{By using} H ₂ if necessary and H ₂ if necessary and O _{2 as} non-Si non-C based gas, it is possible to form a high quality amorphous silicon oxide film or a high quality crystalline silicon oxide film for the above-mentioned reason. It can be formed at high speed and with high uniformity of film thickness and film quality over a large area.

In the fifth example, the raw material gas contains Si as a molecular formula.
And a gas containing Ge, and the non-Si non-C-based gas contains H ₂ to form Si-G.
It is an e-based film. Specifically, for example, the raw material gas is Si
If H ₄ and GeH ₄ are used and H ₂ is used as a non-Si non-C-based gas, a high-quality hydrogenated amorphous silicon germanium film or a high-quality crystalline silicon germanium film can be formed at high speed for the above-mentioned reason. The film can be formed with high uniformity of film thickness and film quality over a large area.

The sixth example is a C-based film formed by a source gas containing a gas containing C in the molecular formula and a non-Si non-C-based gas containing H ₂ . Specifically, for example, CH ₄ and, if necessary, a small amount of O ₂ in the raw material gas,
When H ₂ is used as the non-Si non-C-based gas, a high-quality amorphous carbon film or a high-quality crystalline carbon film can be formed at a high speed over a large area for the reason described above.
The film can be formed with high uniformity of film quality. Specifically, a film such as a diamond film or a diamond-like carbon film can be formed. = Thin Film Device = Next, if the film formed by the Cat-PECVD method of the present invention is used for a thin film device, the following thin film device can be manufactured at high performance and at low cost.

A first example of a thin film device is a photoelectric conversion device. If a film formed by the Cat-PECVD method of the present invention is used for a photoactive layer, high performance characteristics can be realized at high speed, that is, at low cost. Can be. Particularly, in a solar cell which is a representative example of a photoelectric conversion device, the Cat-PEC of the present invention is used.
The high-speed, high-quality, large-area film forming characteristics of the VD method are sufficiently exhibited, and a highly efficient and low-cost thin-film solar cell can be manufactured. Aside from the solar cell, a similar effect can be obtained with a device having a photoelectric conversion function such as a photodiode, an image sensor, or an X-ray panel.

The second example of the device is a photoreceptor device. If a film formed by the Cat-PECVD method of the present invention is used as a photoreceptive layer, high performance characteristics can be realized at high speed, that is, at low cost. Can be. In particular, when used for a silicon-based film in a photosensitive drum, a relatively thick silicon-based film ranging from several μm to several tens μm can be formed with high quality in a short time, which is very effective in reducing the manufacturing cost.

A third device example is a display device.
If a film formed by the Cat-PECVD method of the present invention is used as a driving film, high-performance characteristics can be realized at high speed, that is, at low cost. In particular, when it is used for an amorphous silicon film or a polycrystalline silicon film in a TFT which is a representative example of a large-area device next to a solar cell, it is very effective in reducing the manufacturing cost for the same reason as described for the solar cell. Other than TFT, for example, image sensor, X
The same effect can be obtained with a device having a display function such as a line panel. = Thin-film Si solar cell = Hereinafter, a thin-film Si solar cell as a device according to the present invention will be described with reference to FIG.
12, reference numeral 11 denotes a light-transmitting substrate, 12 denotes a first transparent conductive film, 13 denotes a semiconductor multilayer film, 13a denotes a first semiconductor bonding layer, 13b denotes a second semiconductor bonding layer, and 14 denotes a second transparent bonding layer. The conductive film 15a is a metal film serving as a first extraction electrode;
b is a metal film to be a second extraction electrode.

First, the translucent substrate 11 is prepared. As the translucent substrate 11, a plate material or a film material made of glass, plastic, resin, or the like can be used.

Next, a first transparent conductive film 12 is formed.
As the material of the transparent conductive film 12, SnO ₂ , ITO, Z
Although a known material such as nO can be used, when the subsequent Si film is formed, it is exposed to a hydrogen gas atmosphere due to the use of SiH ₄ and H ₂ .
It is desirable to form a ZnO film having excellent reduction resistance at least as a final surface. As a film forming method, a CVD method,
Known techniques such as a vapor deposition method, an ion plating method, and a sputtering method can be used. The thickness of the first transparent conductive film 12 is set to 60 in consideration of an antireflection effect and a reduction in resistance.
It is adjusted in the range of about 500 nm.

Next, a semiconductor multilayer film 13 is formed. Here, the semiconductor film is pinpin (or n
A tandem type stacked in an (ipnip) configuration will be described as an example.
(Or nip) single-junction type, and the semiconductor film is formed by pinpinpin (or nip).
Of course, the contents described in this embodiment can be applied to a triple-junction-type device or a multi-junction-type device structure of a triple-junction type or more stacked in the configuration of (ipnipnip).

First, a first semiconductor bonding layer 13a including a hydrogenated amorphous silicon film in a photoactive layer is formed. Specifically, it is desirable to have a p-type layer (n-type layer) / photoactive layer / n-type layer (p-type layer) structure (not shown), and to make the photoactive layer i-type. The above notation indicates the order of film formation, meaning lower layer / upper layer.

Here, for the p-type layer (n-type layer), water
Includes amorphous silicon film and microcrystalline silicon film
A crystalline silicon film can be used. The thickness of the material is
It is adjusted in the range of about 2 to 100 nm according to the material. Do
1 × 10 for ping element concentration¹⁸~ 1 × 10^{twenty one}/ C
m^ThreeAs a degree, substantially p⁺Type (n⁺Type). What
SiH used for film formation_Four, H_TwoAnd doping gas
Is B_TwoH₆(PH _Three) Plus CH_FourSuch
If an appropriate amount of gas containing C (carbon) is mixed, Si _xC_1-xfilm
And is very effective for forming a window layer with little light absorption loss.
To reduce dark current components to improve open-circuit voltage
Is also effective. Gas containing O (oxygen) in addition to C
The same applies to mixing an appropriate amount of gas containing N and N (nitrogen).
Effects can be obtained. Here, the formation of the silicon film
As a method, a conventionally known PECVD method or C
The at-CVD method can be used.
The clear method can also be used.

Next, a hydrogenated amorphous silicon film is used for the photoactive layer, and the film thickness is adjusted in the range of about 0.1 to 0.5 μm. The conductivity type is basically i-type,
For the purpose of fine adjustment of the internal electric field intensity distribution, an n ^- type (p ^- type) may be used (in practice, even a non-doped film usually shows a slight n-type characteristic). Here, as a method of forming the hydrogenated amorphous silicon film, a conventionally known PECVD method or Cat-CVD method can be used. However, if the method of the present invention is used, a high-quality hydrogenated amorphous silicon film can be obtained. Since the film can be formed at a high speed and with a large area and with high productivity, it is particularly effective for manufacturing a high-efficiency and low-cost thin-film Si solar cell. Further, according to the present invention, the hydrogen concentration in the film is set to 15
atomic% or less, but more preferably
10 atomic% or less, which is difficult to achieve with the conventional PECVD method,
More preferably, a film having a low hydrogen concentration of 5 atomic% or less can be obtained, so that the degree of photodegradation, which has been a problem of the hydrogenated amorphous silicon film for many years, can be reduced.

Finally, as the n-type layer (p-type layer), a crystalline silicon film including a hydrogenated amorphous silicon film and a microcrystalline silicon film can be used. The thickness is adjusted in the range of about 2 to 100 nm according to the material. The doping element concentration is about 1 × 10 ¹⁸ to 10 ²¹ / cm ³ , and is substantially n ⁺ type (p ⁺ type). In addition, in addition to SiH ₄ , H ₂ used during film formation, and a gas containing C (carbon) such as CH ₄ in addition to a gas such as PH ₃ (B ₂ H ₆ ) as a doping gas, Si _x C _{A 1-x} film is obtained, and a film with less light absorption loss can be formed, and it is also effective in reducing a dark current component for improving an open circuit voltage. A similar effect can be obtained by mixing an appropriate amount of a gas containing O (oxygen) or a gas containing N (nitrogen) in addition to C. Here, as a method of forming the silicon film, a conventionally known PECVD method or Cat-CVD method can be used, but the method of the present invention can be also used.

In order to further improve the junction characteristics, p
A substantially i-type non-single-crystal Si layer or non-single-crystal Si _x C ₁ between the photo-active layer and the photo-active layer or between the photo-active layer and the n-type layer (p-type layer); _-x layer may be inserted. At this time, the thickness of the insertion layer is about 0.5 to 50 nm.

Next, a second semiconductor bonding layer 13b including a crystalline silicon film in the photoactive layer is formed. Specifically, it is desirable to use a p-type layer (n-type layer) / photoactive layer / n-type layer (p-type layer) (not shown), and the photoactive layer is preferably i-type.

Here, as the p-type layer (n-type layer), a crystalline silicon film including a hydrogenated amorphous silicon film and a microcrystalline silicon film can be used. The thickness is adjusted in the range of about 2 to 100 nm according to the material. Doping element concentration is 1 × 1E18 to 1E21 / cm ³
The degree is substantially p ⁺ type (n ⁺ type). In addition,
By mixing an appropriate amount of a gas containing C (carbon) such as CH ₄ in addition to SiH ₄ , H ₂ used during film formation, and a gas such as B ₂ H ₆ (PH ₃ ) as a doping gas, an Si _x C _{1 A -x} film is obtained, which is very effective for forming a window layer with small light absorption loss, and is also effective for reducing a dark current component for improving an open circuit voltage. A similar effect can be obtained by mixing an appropriate amount of a gas containing O (oxygen) or a gas containing N (nitrogen) in addition to C. Here, as a method for forming the silicon film, a conventionally known PECVD method or Ca
Although the t-CVD method can be used, the method of the present invention can of course also be used.

Next, a crystalline silicon film typified by a microcrystalline silicon film is used for the photoactive layer,
Adjust within the range of about μm. The conductivity type is basically i-type, but may be n ^- type (p ^- type) for the purpose of fine adjustment of the internal electric field intensity distribution. At this time, as the film structure, the surface shape after film formation is suitable for optical confinement as an aggregate of (110) -oriented columnar crystal grains generated as a result of preferential growth of the (110) plane among the crystal planes. It is desirable to have a self-generated uneven structure. Here, as a method of forming the crystalline silicon film, a conventionally known PECVD method or Cat-CVD method can be used, but by using the method of the present invention, a high-quality crystalline silicon film can be formed. Since a film can be formed at a high speed and in a large area and with high productivity, it is particularly effective for manufacturing a high-efficiency and low-cost thin-film Si solar cell. Further, according to the present invention, a crystalline silicon film having a hydrogen concentration in the film of 10 atomic% or less can be obtained, but more preferably 5 atomic%.
%, And more preferably, a film having a low hydrogen concentration of 3.5 atomic% or less.

Here, in the case of a crystalline silicon film, most of the hydrogen exists in the crystal grain boundary portion, and the bonding state of the hydrogen with Si and its density depend on the quality of the crystal grain boundary (in the crystal grain boundary). (Proportional to the reciprocal of the carrier recombination rate). In other words, as the density of SiH ₂ bonds, in which two H atoms and two other Si atoms are bonded to one Si atom present at the crystal grain boundary, is higher, the so-called post-oxidation phenomenon (after the film is formed, When exposed to the atmosphere, O ₂ , CO ₂ ,
Oxygen-containing gas components such as H ₂ O diffuse, adsorb, and oxidize at the crystal grain boundaries in the film, causing a change in the bonding state of the crystal grain boundaries.) Although the deterioration of the film quality as a whole (that is, the deterioration of the characteristics over time) is caused as a whole, the lower the hydrogen concentration in the film, the lower the SiH ₂ bond density at the crystal grain boundaries. It is possible to reduce a temporal deterioration phenomenon caused by the post-oxidation phenomenon. Specifically, when the hydrogen concentration in the film is set to 5 atomic% or less, the deterioration rate with time can be suppressed to about several% or less, and the hydrogen concentration in the film is set to 3.5 atomic% or less.
If it is set to omic% or less, the deterioration rate with time can be made almost zero. As a result, a more efficient solar cell can be manufactured.

Finally, as the n-type layer (p-type layer), a crystalline silicon film including a hydrogenated amorphous silicon film and a microcrystalline silicon film can be used. The thickness is adjusted in the range of about 2 to 100 nm according to the material. The doping element concentration is about 1 × 10 ¹⁸ to 10 ²¹ / cm ³ , and is substantially n ⁺ type (p ⁺ type). In addition, in addition to SiH ₄ , H ₂ used during film formation, and a gas containing C (carbon) such as CH ₄ in addition to a gas such as PH ₃ (B ₂ H ₆ ) as a doping gas, Si _x C _{A 1-x} film is obtained, and a film with less light absorption loss can be formed, and it is also effective in reducing a dark current component for improving an open circuit voltage. A similar effect can be obtained by mixing an appropriate amount of a gas containing O (oxygen) or a gas containing N (nitrogen) in addition to C. Here, as a method of forming the silicon film, a conventionally known PECVD method or Cat-CVD method can be used, but the method of the present invention can be also used.

In order to further improve the junction characteristics, an i-type non-conductive layer is formed between the p-type layer (n-type layer) and the photoactive layer or between the photoactive layer and the n-type layer (p-type layer). A single-crystal Si layer may be inserted. At this time, the thickness of the insertion layer is about 0.5 to 50 nm.

Next, a second transparent conductive film 14 is formed.
As a transparent conductive film material, Sn as a metal oxide material is used.
O ₂ , ITO, ZnO, or the like can be used. Known techniques such as a CVD method, an evaporation method, an ion plating method, a sputtering method, and a sol-gel method can be used as a film forming method. The second transparent conductive film 14 can be omitted when high efficiency is not particularly required.

Finally, a metal film 15a and a metal film 15b to be the extraction electrodes 1 and 2 are formed. As the metal material, it is desirable to use Al, Ag, or the like, which has excellent conductivity and light reflection properties. As the film forming method, known techniques such as a vapor deposition method, a sputtering method, an ion plating method, and a screen printing method can be used. The electrode pattern can be formed into a desired pattern by using a masking method, a lift-off method, or the like. At this time, the film thickness is about 0.1 μm or more. When the adhesive strength between the metal film 15a and the second transparent conductive film 14 or between the metal film 15b and the first transparent conductive film 12 is low, a thin metal film, such as Ti, which is easily oxidized has a thickness of 1.
It is preferable to intervene between the two films at about 10 to 10 nm.

When a light confinement structure is introduced for the purpose of further improving the conversion efficiency, Japanese Patent Application No. 2002-78.
The structure as described in Japanese Patent No. 196 can be adopted.
That is, the maximum height Rmax of the unevenness at the interface between the first transparent conductive film and the semiconductor multilayer film is smaller than the maximum height Rmax of the unevenness at the interface between the second transparent conductive film and the metal film. (At this time, the maximum height Rmax of the unevenness at the interface between the first transparent conductive film and the semiconductor multilayer film)
Is desirably 0.08 μm or less.
Height Rma of unevenness at the interface between the transparent conductive film and the metal film
x is preferably 0.05 μm or more)
The maximum height Rmax of the unevenness at the interface between the semiconductor multilayer film and the second transparent conductive film is larger than the maximum height Rmax of the unevenness at the interface between the first transparent conductive film and the semiconductor multilayer film, and A structure characterized by being smaller than the maximum height Rmax of the unevenness at the interface between the second transparent conductive film and the metal film, and further, the interface between the light-transmitting substrate and the first transparent conductive film is made uneven. With a structure characterized by having a structure, an effective light confinement structure can be formed, so that the photocurrent density increases and higher conversion efficiency can be realized.

As described above, according to the present invention, a high-quality Si thin film can be formed at high speed with a large area and with high productivity.
A solar cell can be manufactured.

[0100]

According to the Cat-PECVD method of claim 1 or 2, the heating is carried out by a raw material gas containing a gas containing Si and / or C in a molecular formula and a thermal catalyst disposed in a gas introduction path. The non-Si non-C-based gas composed of a gas not containing Si and C in the molecular formula to be formed is separated from each other and passes through the hollow portion of the antenna electrode having a hollow structure installed in the film forming space. Gases ejected from the plurality of gas outlets provided in the antenna electrode into the film forming space and mixed and ejected into the film forming space are decomposed by plasma generated by the antenna electrode connected to a high-frequency power supply. When activated, a film is deposited on the substrate disposed opposite to the antenna electrode in the film-forming space,
High-speed and high-quality film formation of a Si-based film or a C-based film can be realized over a large area with a uniform film thickness and a uniform film quality. Further, the antenna electrodes are arranged in parallel to form an array-shaped antenna electrode unit, and high-frequency power from the high-frequency power source is distributed and introduced to each antenna electrode of the array-shaped antenna electrode unit. Therefore, normally, more power distribution can be realized with a smaller number of high-frequency power supplies, which is effective in reducing equipment costs.

Further, C of claim 3 to claim 7 and claim 9
According to the at-PECVD method, a more uniform large-area plasma can be generated.

According to the Cat-PECVD method of the eighth aspect, the generation and growth of powder can be suppressed, which is effective for improving the film quality.

According to the film of the present invention, the uniformity of film thickness and film quality is high over a large area, and high-performance and rapid production is possible. It can be.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically illustrating an example of an apparatus for realizing a Cat-PECVD method according to the present invention.

FIG. 2 is a cross-sectional view schematically illustrating an example of an apparatus for realizing the Cat-PECVD method according to the present invention (an example in which a heater is installed on a wall surface of a film forming chamber).

FIG. 3 is a diagram schematically illustrating an example of an antenna electrode arrangement for realizing the Cat-PECVD method according to the present invention, and is a cross-sectional view of a film forming surface of a base.

FIG. 4 is a diagram schematically illustrating an example of an antenna electrode arrangement for realizing the Cat-PECVD method according to the present invention, and is a cross-sectional view as viewed from a center axis direction of the antenna electrode.

FIG. 5 is a diagram schematically illustrating an example of an antenna electrode with a built-in thermal catalyst for realizing the Cat-PECVD method according to the present invention, and is a longitudinal sectional view when the center axis direction of the antenna electrode is vertical.

FIG. 6 is a perspective view schematically illustrating an example of an antenna electrode with a built-in thermal catalyst for realizing the Cat-PECVD method according to the present invention.

FIG. 7 is a cross-sectional view schematically illustrating an example of an antenna electrode with a built-in thermal catalyst (two built-in thermal catalysts) realizing the Cat-PECVD method according to the present invention.

FIG. 8 is a configuration diagram schematically illustrating a film processing system according to the present invention.

FIG. 9 is a cross-sectional view schematically illustrating an example of a conventional PECVD apparatus.

FIG. 10 is a cross-sectional view schematically illustrating an example of a conventional Cat-CVD apparatus.

FIG. 11 is a cross-sectional view schematically illustrating an example of a Cat-PECVD apparatus.

FIG. 12 is a sectional view schematically showing an example of a thin film device according to the present invention.

[Explanation of symbols]

101: Raw material gas inlet 102: Non-Si non-C gas inlet 103: thermal catalyst 104: Power supply for heating the thermal catalyst 105: Plasma 106a: Antenna electrode with built-in thermal catalyst 106b: Antenna electrode without built-in thermal catalyst 107: High frequency power supply 107a: High frequency power supply 107b: High frequency power supply 108a: phase converter 108b: power distributor 108c: phase converter 108d: power distributor 109: Substrate 109a: Substrate 109b: Substrate 110: Substrate heater 111a: Gas outlet for antenna electrode with built-in thermal catalyst 111b: Gas electrode outlet for antenna electrode without built-in thermal catalyst 112: insulating member 113: Chamber 114a: hollow portion (non-Si non-C gas path) 114b: hollow portion (source gas path) 115: Inner wall heater

   ────────────────────────────────────────────────── ─── Continuation of front page    F term (reference) 4K030 AA06 AA09 BA09 BA27 BA29                       BA30 BA31 BA37 BA40 BA44                       BB03 CA12 CA14 CA17 EA06                       FA04 FA10 KA17 KA30 KA45                       LA15                 5F045 AA08 AB03 AB04 AB32 AB33                       AC01 AC11 AC12 BB02 BB08                       BB09 CA13 EF03 EF08 EH02                       EH04 EH05 EH08                 5F051 AA05 AA16 BA12 BA14 CA16                       DA04 DA15 FA03 FA04

Claims (21)

[Claims] 1. A non-product gas comprising a source gas containing a gas containing Si and / or C in a molecular formula, and a gas containing no Si and C in a molecular formula heated by a thermal catalyst disposed in a gas introduction path. The Si non-C-based gas is separated from the plurality of gas outlets provided in the antenna electrode through a hollow portion of the antenna electrode having a hollow structure installed in the film forming space in a state where they are separated from each other. The gas spouted into the film space, the gas spouted into the film formation space and mixed is decomposed and activated by the plasma generated by the antenna electrode connected to the high-frequency power supply, and is applied to the antenna electrode in the film formation space. In a Cat-PECVD method in which a film is deposited on a substrate placed opposite to the substrate, a plurality of the antenna electrodes are arranged in parallel to form an array antenna electrode unit, The high-frequency power from the high-frequency power source is distributed and introduced to each antenna electrode of the array-shaped antenna electrode unit.
-PECVD method. 2. The Cat-PECVD method according to claim 1, wherein there are a plurality of said high frequency power supplies. 3. The phase of the high-frequency power guided to each antenna electrode of the array-like antenna electrode unit is:
The Cat-PECVD method according to claim 1, wherein the Cat-PECVD method is different at least between adjacent antenna electrodes. 4. The Cat-PEC according to claim 1, wherein feed points of adjacent antenna electrodes of the array-shaped antenna electrode unit are located in opposite directions.
VD method. 5. The Cat-PECVD method according to claim 1, wherein a plurality of high-frequency powers having different frequencies are superposed and supplied to the antenna electrode. 6. The Cat according to claim 1, wherein high-frequency powers having different frequencies are applied to adjacent antenna electrodes of the array-shaped antenna electrode unit.
-PECVD method. 7. The Cat-PECVD method according to claim 1, wherein the frequency of the high-frequency power supplied to the antenna electrode fluctuates and modulates with time. 8. The C according to claim 1, wherein high-frequency power is intermittently supplied to the antenna electrode.
at-PECVD method. 9. The Cat-P according to claim 1, wherein the frequency of the high-frequency power supply is 27 MHz or more.
ECVD method. 10. The Ca according to claim 1, wherein
A film formed by a t-PECVD method. 11. The film according to claim 1, wherein the source gas contains a gas containing Si in a molecular formula, but does not contain a gas containing C in a molecular formula, and the non-Si non-C-based gas contains H _2. The film according to claim 10, wherein the film is a Si-based film formed by performing the method. 12. The Si-based film is made of hydrogenated amorphous S
12. The film according to claim 11, wherein the film is an i film, and the hydrogen concentration in the film is 15 atomic% or less. 13. The Si-based film is a crystalline Si film,
The film according to claim 11, wherein the hydrogen concentration in the film is 10 atomic% or less. 14. The film is formed by including a gas containing Si in a molecular formula and a gas containing C in a molecular formula in the raw material-based gas and H _{2 in the} non-Si non-C-based gas. 2. A film according to claim 1, wherein said film is a Si-C film.
The membrane according to 0. 15. The film according to claim 1, wherein the source gas contains a gas containing Si in a molecular formula, the non-Si non-C gas contains H ₂ , and the source gas or a non-Si / non-C gas. The film according to claim 10, wherein the film is a Si-N-based film formed by including a gas containing N in a molecular formula in at least one of the gases. 16. The film according to claim 1, wherein the source gas contains a gas containing Si in a molecular formula, and the non-Si non-C gas contains a gas containing O in a molecular formula. The film according to claim 10, wherein the film is an O-based film. 17. The film according to claim 1, wherein the source gas includes a gas containing Si in a molecular formula and a gas containing Ge.
film according to claim 10, characterized in that the i non-C-based gas is a Si-Ge-based film formed by the inclusion of H _2. 18. The film according to claim 1, wherein the source gas contains a gas containing C in a molecular formula, and the non-Si non-C gas contains H.
11. The film according to claim 10, wherein the film is a C-based film formed by including ₂ . 19. A thin-film device comprising the film according to claim 10. 20. The thin-film device, comprising: a photoelectric conversion device;
20. The thin film device according to claim 19, which is a photoreceptor device or a display device. 21. The thin-film device according to claim 19, wherein the substrate according to claim 1 has a shape of a flat plate, a cylinder, or a film.