JPH056877A - Etching method of carbon film - Google Patents

Abstract

PURPOSE:To prevent impurities from creeping into a semiconductor layer by a method wherein a carbon film is plasma-etched by using a fluoride gas. CONSTITUTION:One pair of electrodes 9, 10 are arranged at the upper part and the lower part or on the right and the left of a reaction furnace 25 into which a substrate 1 has been inserted; an electric furnace 5 is installed at their outside; the substrate 1 is heated to 100 to 40 deg. C. As reactive gases, a carrier gas 13 by hydrogen or helium, diborane 14, phosphine 15 and silane 16 are introduced. When a reaction product which has adhered to the innerwall or the surface of the reaction furnace 25 or a holder 2 is removed CF4 or CF4 +O2 (at 2 to 5 %) is introduced, an electromagnetic energy is applied, fluorine radicals are generated, a vapor etching operation is executed and the reaction product is removed. In this plasma discharge operation, a reactive gas is mixed via a mixing chamber 8, it is decomposed or reacted in an excitation chamber 26, and a silicon carbide film is formed by using a spatial reaction forming a reaction product on the substrate 1. Thereby, a possibility that impurities creep can be eliminated.

Description

Detailed Description of the Invention

The present invention uses the plasma vapor phase method to obtain reproducibility,
The present invention relates to a method for manufacturing a semiconductor device with favorable characteristics.

According to the present invention, a first semiconductor device having P-type and N-type semiconductor layers is formed on a substrate provided in a reaction furnace by a plasma vapor phase method, and then N or P-type impurities of the semiconductor device are formed. To be re-emitted from the inner wall of the reactor or the holder of the substrate into the P or N type semiconductor layer to be produced next, and to prevent it from being mixed in at a concentration of 10 ¹⁵ to 10 ¹⁸ cm ^-3 , Between these steps, a step of forming a coating film for intrinsic or substantially intrinsic (hereinafter referred to as I layer) coating on the previously formed semiconductor layer (in this case, coating the film formed at the beginning of the next step) The purpose is to remove the past history substantially.

Further, a step of removing the semiconductor layer formed previously from the inner wall of the reaction apparatus, the surface of the substrate holder, etc., by converting the reactive gas such as CF into plasma is provided. To aim.

Thus, the RUN-T can be reproduced with good reproducibility.
The characteristics of O-RUN can be reduced and the obtained characteristics can be made extremely excellent.

Further, according to the present invention, in a semiconductor device having at least one junction, particularly PIN, PI, NI or PN junction on a substrate provided in the reaction furnace, inner walls of the reaction furnace, particularly plasma atoms or reactive gas collide with each other. In order to prevent impurities, particularly oxygen and alkali metal atoms, from being released from the inner wall, it is an object to form an intrinsic or substantially intrinsic semiconductor layer such as non-single-crystal silicon in advance on these surfaces.

In order to prevent re-emission with the coating for substantially removing them, the present invention causes the semiconductor layer to output the electromagnetic energy Po necessary for manufacturing a semiconductor device, eg, Po.
~ 100W, temperature To, for example, 200 ~ 320 ℃,
Po-10 W (however, at least 5 W) to Po + 30 W, and To-50 ° C. to To + 50 ° C. are particularly preferably prepared under the same or substantially the same conditions as those of Po and To.
It is characterized in that it is formed to a thickness of 2-1 μ.

Regarding the conventional plasma CVD method, a semiconductor device having a PIN junction or the like has been manufactured in one reaction furnace. However, if this joining is repeated, it suffers from completely indefinite deterioration and variation, and only the reliability of the semiconductor device is unsuitable.

As a result of one reason for this, the most significant cause is that oxygen and alkali metals adhering to the inside of the reaction furnace are mixed in the semiconductor layer, resulting in a decrease in electrical conductivity. Even if 1PPM is mixed, the dark conductivity of 10 ^-6 (Ωcm) ^-1 is 10 ^-8 (Ωcm) ^-1 and 1/100
Had been lowered to.

Further, even in the case of alkali metal, the incorporation of 5PPM causes a decrease in the conductivity of P-type and I-type and a decrease in the conductivity of the transparent conductive film.

In order to prevent these contaminations, a semiconductor layer having a thickness of 0.2 to 2 μm is previously formed on the inner wall of the reaction furnace or the portion of the substrate holder (also called a boat) which is sputtered by the reactive gas due to the plasma. It was extremely important that they be formed and coated. Further, for the deterioration of reproducibility characteristics, the last step of manufacturing one semiconductor device is to form an N or P type semiconductor layer, and the next first step is to form a P or N type semiconductor layer. At this time, the first impurity such as phosphorus is mixed in the P-type semiconductor at a concentration of 10 ¹⁵ to 10 ¹⁸ cm ^-3 . Therefore, P
For example, even if a p-type layer is formed by adding boron to a concentration of 10 ¹⁸ to 10 ²¹ cm ⁻³ , the electric conductivity of the type semiconductor layer is extremely poor because recombination centers increase due to the incorporation of phosphorus.
When there is no mixture, 10 ^-2 to 10 ⁺¹ (Ωcm) ^-1 against 10
Only ^-6 to 10 ^-4 (Ωcm) ^-1 and 1/100 to 1/1000 were obtained.

Therefore, in the PIN photoelectric conversion device, the efficiency of 2 to 4% was obtained only with the variation of each run of ± 200%, which was not preferable. However, according to the method of the present invention, it has become possible to obtain a high conversion efficiency of about 3 to 5 times that of 8 to 10%.

In order to reduce the effect of this impurity oxygen doping, a patent application for semiconductor device fabrication method filed by the inventor of the present invention is 56-55608 (original display 53-1528).
87 application on December 10, 1978) is known. For example, when trying to make a PIN semiconductor device, each P
Layers, I layers, and N layers are made into independent reaction furnaces, and the substrate is moved between the layers. This method can have the same measures as those of the present invention, and can obtain extremely preferable electric characteristics. However, in that case, the apparatus is three times as much as the one-chamber system, and the manufacturing cost is 2.5 to 3 times more expensive. Further, it has a defect that it is not suitable for mass production.

The present invention is particularly effective in such a reactor, particularly in a horizontal reactor. In addition, it is particularly effective when trying to make a large number of semiconductor devices on a substrate, and has a major feature that the manufacturing cost including depreciation of each semiconductor device can be reduced to 1/100 of that of a vertical reactor. is doing. That is, the present invention is directed to such a horizontally arranged reactor or reactor (10 to 30 cmφ,
A method using a length of 1 to 5 m) will be mainly described.

An electrode for supplying electromagnetic energy for converting a pair of reactive gases into plasma is provided outside the reaction tube, and a heating device is provided outside the electrode so as to surround the reaction tube and the electrode, and the inside of the reaction furnace is provided. A reactive gas is caused to flow in the direction of the furnace, and the substrates are arranged along the flow of this gas.

Further, substrates are arranged in the apparatus in a direction perpendicular or parallel to the electromagnetic field generated by a pair of electrodes, and the substrates are arranged in a plurality of rows or columns to form a substrate of 2 to 20 cm square, for example, a substrate of 10 cm square in 20 stages. It is mainly described that a film, particularly a silicon, carbon silicon carbide or silicon germanium, germanium film, that is, a semiconductor film mainly containing a tetravalent element, is formed at once on 400 formation surfaces of 20 rows in total.

The present invention relates to a reactive gas composed of a hydride or a halide (carbide silicide gas) having a carbon-silicon bond, a silicide gas such as silane (Si _n H _{2n + 1} n ≧ l) or acetylene. A non-single crystal silicon carbide, silicon or carbon-based coating film is formed on the surface to be formed by using a hydrocarbon at a reaction furnace pressure of 0.05 to 1 torr for 100 to 40
The present invention relates to a plasma vapor phase method for forming at a temperature of 0 ° C.

In the present invention, the reactive gas further contains an impurity gas containing trivalent impurities B, Al, Ga and In, such as diborane (B ₂ H ₆ ), and an impurity gas containing pentavalent impurities such as phosphine (PH). ₃ ) or arsine (A
sH ₃ ) is gradually added so that the P-type layer, the I-type layer and the N-type layer are further laminated in the order of PIN in close contact with the substrate having the surface to be formed, and this is repeated for stable production. The purpose is to Further, according to the present invention, a semiconductor having an amorphous structure (referred to as AS), semi-amorphous (semi-amorphous, hereinafter referred to as SAS) having a crystallinity of 5 to 100 Å, or 5 to 200 Å by the power of electromagnetic energy to be turned into plasma A non-single-crystal semiconductor film such as a semiconductor having a micro-polycrystal (hereinafter referred to as PC) structure having a size of 1 is produced. When stronger electromagnetic energy is applied, the substrate surface is likely to have an amorphous structure sputtered with defects. In order to eliminate such a defect structure, the substrates are separated from each other by 10 to 40 mm, typically 20 to 25 mm, and even when high energy of 200 to 500 W is required for the plasma reaction, this spice is formed on the surface to be formed. It is characterized in that it has characteristics equivalent to those obtained by controlling the distance for obtaining substantial plasma energy by the distance between the substrates and forming a film with a weak power of substantially 2 to 20 W.

Therefore, in the present invention, silicon carbide (SixC _1-x 0 <x <is added to the reactive gas as the starting material.
When trying to make 1), a material having a carbon-silicon bond was used. That is, a hydride or halide having a carbon-silicon bond, such as tetramethylsilane (Si (CH
₃ ) ₄ ) (simply called TMS), tetraethylsilane (Si
(C ₂ H ₅ ) ₄ ), (Si (CH ₃ ) xCl _4-x (1≤x≤3)
A reactive gas such as Si (CH ₃ ) xH _4-x (1 ≦ x ≦ 3) is used to facilitate Si—C bond formation in the reaction product.

When a film containing silicon as the main component is to be obtained, Si _n H _{2n + 2} (n ≧ 1) silane, SiF ₄ or a mixed gas thereof is used. When trying to obtain carbon, acetylene (C ₂ H ₂ ) or ethylene (C
₂ H ₄ ) was mainly used. By doing so, silicon (Si), silicon carbide (SixC _1-x 0 <x <1) or carbon (C) (when these are combined, SixC _1-x (0 ≦ x
Since it can be expressed as ≦ 1), hereinafter, when referring to silicon carbide, SixC _1-x (meaning 0 ≦ x ≦ 1) is produced).

Further, trivalent or pentavalent impurities are added here to form a P-type, an I-type (substantially true without artificially adding impurities including intrinsic or autodoping) and N-type from the surface to be formed. A half body or a half insulator was produced.

Further, when such a reactive gas is used, the electromagnetic energy of 50 W or less under a pressure of 1 atm or less, particularly 0.01 to 10 torr, typically 0.3 to 0.6 torr, is applied to the reaction furnace, for example. 0.01-100MHz
In particular, it is possible to form a coating at 500 KHz or 13.56 MHz. That is, a low energy plasma CVD apparatus could be obtained.

When a high energy plasma atmosphere of 50 to 500 W is further applied, the formed silicon carbide is crystallized, and as a result, 0.1 to 5% of boron or phosphorus in the P type or N type (here, (BH or PH) / (carbide gas or silicon carbide gas + silicide gas ratio) is added), the electrical conductivity was 10 ^-9 to 10 ^-3 (Ωcm) ^-1 at low energy. Is 10 ^-6
We were able to increase it to about 10 times ⁺² (Ωcm) ^-1 .

Further, the silicon carbide obtained by using this high energy method could have a so-called SAS structure having a microcrystalline structure with a size of 5 to 200 Å. In such a SAS, the ionization rate of the P or N type impurity serving as an acceptor or a donor is 97 100%,
All of the added impurities could be activated. The plasma vapor phase method of the present invention will be described below with reference to the drawings.

FIG. 1 shows an outline of a plasma CVD apparatus using the present invention. In FIG. 1, a substrate (1) having a surface to be formed is held by a square quartz holder, and in FIG.
It has a total of 14 rows and 14 columns. The substrate and the holder are installed in advance in a separate chamber (29) in front of the reactor from an inlet (30), and a valve (32) and a rotary pump (3
Vacuum squeezing is performed by 3). Open and close doors (3
4) is opened and introduced into the reaction furnace by an automatic feeder, and the mixer mixing plate (35) is also placed at the same time. These were performed in a vacuum state in both the reaction furnace and the separate room, and efforts were made to prevent oxygen (air) from entering the reaction furnace at all. Further, by closing the opening / closing door (34), the substrate was placed between the electrodes (9) and (10) as shown in the drawing.

Each substrate is 10 to 40 mm, typically 20 to 2
The reactive gases from the holder are arranged at intervals of 5 mm, and a mixer (8) is provided in front of the reaction furnace (25) to form a laminar flow, and these reactive gases are evenly distributed in the space between the substrates. It is provided to be injected into. The formation surface is a bottom surface of the substrate or a side surface vertically arranged with the back surfaces of the substrates overlapped with each other.

Further, the drawing shows a structure in which the reaction system is seen from above, and the substrates (1) are arranged vertically with their back surfaces aligned with each other. As described above, it is extremely important to remove the flake to the lower part by utilizing gravity, considering the mass production yield. Further, in the reaction furnace (25) in which the substrate (1) is inserted, an electric field of electromagnetic energy is perpendicular to or parallel to the substrate (especially if it is parallel, it is easy to obtain the uniformity of the coating). (B) In particular, a pair of electrodes (9) and (10) are arranged vertically or horizontally so as to be added as shown in (B). An electric furnace (5) is provided outside this electrode, and the substrate (1) is 100 to 400.
C. Typically, it is heated to 300.degree.

As the reactive gas, hydrogen or helium carrier gas such as helium is added from (13), trivalent impurity diborane (14) is added, and pentavalent additive phosphine is added from (15) to tetravalent. Silane gas silane, which is a substance, was introduced from (16).

A reactive gas T having a carbon-silicon bond is also used.
When MS (20) is used, it is stored in the stainless steel container (21) because it is a liquid in the initial state. This container is controlled at a predetermined temperature by the electronic thermostatic layer (22).

This TMS has a boiling point of 25 ° C., the rotary pump (12) is evacuated through the valve (11),
0.01 to 10 torr, especially 0.02 to 0.
It was kept at 4 torr. By doing this, a pressure lower than 1 atm results in no TM
S can be vaporized. This vaporized TMS is 1
Introducing into the reaction furnace at a concentration of 00% via a flow meter enables the flow rate to be controlled more accurately than in the conventional method in which the container (21) is bubbled to release the reactive gas. , Technically important.

When the flow meter was clogged for practical use, a helium was introduced from (24) in the drawing. In addition, the reaction tube (2
5) or when removing the reaction product adhering to the inner wall or surface of the holder (2), CF ₄ or CF ₄ + O ₂ (2 to 5%) is introduced from (17), and electromagnetic energy is applied to add fluorine radicals. Was generated and vapor-phase etching was performed to remove.

Further, in this plasma discharge, after the reactive gas is mixed into the mixing chamber (8), the excitation chamber (2
In 6), a spatial reaction in which decomposition or reaction was caused and a reaction product was formed on the substrate was mainly used. As the electromagnetic energy, DC or high frequency was mainly used from the power source (4).

In this way, a silicon carbide coating film was formed on the surface to be formed. For example, the substrate temperature was 300 ° C., the high-frequency energy output was 25 W, silane or TMS was 50 cc / min, and He was 250 cc / min as a carrier gas. With (reactive gas / He) 5, a film growth rate of 160Å / min could be obtained.

Further, for this film formation, a PIN junction, P
An N junction, a PI, an NI junction, a PINPIN junction, etc. were formed by gradually laminating reaction products required to have the required thickness on the substrate.

After the coating film has been formed on the surface to be formed in this way, after the reactive gas is sufficiently purged from the reaction tube, the opening / closing door (34) is opened and the mixer mixing plate (35). , The substrate on the jig (3) is placed in a separate chamber (29) by an automatic drawing tube, and the reaction cylinder and the separate chamber are both vacuumed (0.01
(below torr) and moved. Further, after closing the opening / closing door (34), the valve was opened from (31) in another room to fill it with air to bring it to atmospheric pressure, and then the substrate having the jig and the film formed thereon was taken out.

As is clear from the above examples, according to the present invention, after the reactive gas is mixed in the mixer (8), the exhaust port (6) performs a random motion in a layered state (microscopically in a plasmaized state). The substrate is arranged in parallel with this flow, and a film is formed on the surface to be formed to a thickness of 0.1 to 3 μ with a variation of ± 5% or less. There is.

Further, at this time, the plasma is generated by utilizing the glow discharge method, and the feature is that the electrode is arranged outside the reaction cylinder so that the plasma is uniformly generated on a large amount of the substrates.

Further, in forming the film, 7 steps 2 as shown in the drawing.
If the reaction cylinder is lengthened to 20 rows and 20 rows instead of rows, it is not 0.4 torr but 0.2, 0.1,
The lower pressure of 0.05 torr is important for obtaining the uniformity of the film quality, particularly the uniformity of the front row and the last row.

Further, in order to prevent mixing of uncontrollable oxide gas such as oxygen into the reaction tube, a separate chamber was provided, and it was combined with the work in the atmosphere through this separate chamber. Was very important to obtain reproducibility of.

FIG. 2 shows the relationship between the arrangement of the substrate (1) and the electrodes (9), (10) as seen from the direction of the exhaust port (6) in the drawing of FIG. In the drawing, (A) shows the substrates arranged horizontally and the electromagnetic fields of the electrodes (9) and (10) arranged horizontally. In this case, the number of substrates that can be introduced at one time can be increased.

In FIG. 2B, the electromagnetic fields by the electrodes (9) and (10) and the substrate (1) are both vertical, and the number of substrates arranged is twice that of (A).

FIG. 3 shows an operation procedure chart of the semiconductor device manufacturing method of the present invention. "0" in the drawing
(49) is 0.01 torr due to evacuation of the reactor.
Retention below r is shown. Furthermore, the "1" (40) indicates the coating of silicon or silicon carbide on the reactor or reactor and the holder according to the invention. This coating is shown in detail in FIGS. 3 (B) and 3 (C). Figure 3 (B)
To 0.01 torr or less by vacuuming (49)
After holding it for 0 to 30 minutes, hydrogen is
Plasma cleaning was performed at an output of 30 to 50 W for 30 minutes to remove adsorption, moisture and oxygen. After further removing the hydrogen, the helium is simultaneously set to 3 by (51).
Plasma was generated for 10 to 30 minutes with an output of 0 to 50 W, and hydrogen on the surface was further removed. This hydrogen plasma generation (5
For 0), when HCl or Cl is added to hydrogen at a concentration of 1 to 5%, chlorine radicals are simultaneously generated, and the radicals exist in the holder such as quartz such as a sodium. Has the effect of sucking out alkali metals. Therefore, the concentration of sodium, water, oxygen, etc. at the background level is 10 ^{14 in the} formed film.
It was a very important pretreatment step, because it could be less than cm ^-3 .

When this chlorine was added, it was also effective to remove chlorine adsorbed on this wall surface by sputtering with an inert gas (51).

Thereafter, these systems are evacuated, and then silane which is a silicide gas or TMS which is a silicon carbide is introduced and decomposed by plasma energy to obtain 0.1 to 2 μm.
The thickness is typically 0.2 to 0.5 μ. When these films are formed, the region where high electromagnetic energy is applied, that is, the region where impurities are likely to be re-emitted, is particularly thick and easy to stick, which gives doubly preferable results.

Even when the complicated pretreatment process of the present invention is not performed, after vacuuming as shown in FIG.
Silicon or silicon carbide in (52) is also 0.1 to
It was effective to form 2μ and prevent the re-release of oxygen and alkali metal from the reactor wall.

Further, in FIG. 3A, for manufacturing a semiconductor device, substrate coating, system vacuum drawing (41), P or N type semiconductor manufacturing (42), I type semiconductor layer manufacturing (43). , Manufacturing an N-type semiconductor layer (44),
A first semiconductor device was produced (48). It goes without saying that this semiconductor device must be manufactured according to a device design specification having at least one junction such as PI, NI, PIN, PN.

After this, the same semiconductor as the I-type semiconductor layer shown in (46) or the semiconductor layer shown in (42) is added to this system only for the reaction furnace or for the reaction system in which the reaction furnace and the holder are inserted and installed. The layer coating was such that the debris from step (44) used in the previous fabrication of the semiconductor device did not affect the next run. The details are shown in FIGS. 3 (B), (C), (D), and (E).

That is, as shown in FIG. 3B, the semiconductor layer is formed in the first step of vacuum drawing (49) hydrogen plasma discharge (50), helium plasma processing (51), and semiconductor device run as in the above-mentioned pretreatment. It has a process (52). However, these (50) and (51) are already (46) in (A)
Therefore, it is generally sufficient to form a semiconductor layer having a thickness of 0.1 to 2 μm in (52) of (C).

Further, in order to eliminate the history of the previous semiconductor device fabrication (40), that is, the previous run, (D), (E)
You may perform the plasma etching process shown in FIG. That is, in FIG. 3B, vacuum suction (49) CF or CF + 0 (about 5%) was introduced from (17) in FIG. 1 and plasma etching (53) was performed for 20 to 1 hour. A vacuum is further applied, and then a hydrogen plasma treatment (50) is performed for 10 to 30 minutes to remove the C and F residues.
A semiconductor layer having a conductivity type and components similar to those of the semiconductor layer (42) of I-type of 5 to 0.5 μm or the first run in the next step was prepared. This method was the most thorough and guaranteed reproducibility.

A simple method is shown in (E) (49).
The steps of vacuum evacuation, plasma etching (53) and removal of residual adsorption gas (50) were performed.

As a result, P or N-type impurities are separated from each other () between the final step (44) of the fabrication (48) of the first semiconductor device and the first step (42) of the next step (48). It was possible to eliminate the possibility of contamination in 42). It was also possible to prevent the addition of additives such as carbon and germanium in (44) in (42).

FIG. 4 shows the result of evaluation of the effect by the method of the present invention.

FIG. 4 shows the result of a photoelectric conversion device manufactured using the method of the present invention. In this case, ITO is formed on a metal such as a stainless substrate or a glass which is a transparent substrate as a substrate.
Of 500 to 2000Å, and a substrate having a multi-layered electrode on which tin oxide or antimony oxide was formed to a thickness of 100 to 500Å. On top of this, P-type silicon carbide (SixC _1-x 0 ≦ x ≦ 1) (for example, x = 0.3 to
0.5) to a thickness of 100 to 300 Å and to this upper surface is added intrinsic or substantially intrinsic AS or SAS silicon.
N-type silicon carbide (SixC _1-x 0 ≦ x ≦ 1 such as x = 0.3 to 0.5) is formed on the upper surface to a thickness of 4 to 0.7 μm.
Was made to have a thickness of 100 to 300 Å. The specifications of the P, I and N type semiconductors are shown in FIG.
(42), (43), (44) in the chart of
(42) .....

Further, after this, in this process, ITO of 600 to
A photoelectric conversion device was made by forming a thickness of 800 Å or an aluminum metal film by a vacuum deposition method. The conversion efficiency is shown in FIG.

With a cell size of 1 cm ² , AMl (100 m
The value of (70) was obtained when the pretreatment (40) was not added under the condition of W / cm ² ) in 3% of (71) and when the pretreatment was performed. Furthermore, the efficiency (60) of the run (every production day) changes due to the addition of the intermediate step (46), and (61) is obtained without any addition.

The efficiency of (60) can be 11 to 9%, while 1 to 4 when the method of the present invention is not used.
There was only%.

Further, when the cell area was set to 100 cm ² , the efficiency of 7 to 9% could be obtained using the method of the present invention, while it was 0 to 3% without the method of the present invention. In particular, those having no diode characteristics had 30% or more and could not be manufactured.

FIG. 4B shows electric conductivity values when an I-type silicon semiconductor is formed in the step of forming a P-type semiconductor in the surface step.

When a P-type semiconductor is formed in the previous step and the pretreatment of the intermediate treatment method of the method of the present invention is not performed, the electric conductivity by light irradiation of AM1 is (65). In some cases, the reverse of the dark conductivity (64) was observed, and the value was 10 ⁻⁶ to 10 ^−4, which was large and varied. On the other hand, when the pretreatment of the present invention was performed, photoconductivity (70) and dark conductivity (70 ') were obtained. When the intermediate treatment was performed, photoconductivity (62) and dark conductivity (63) were obtained. These clearly show how important the prevention of the doping effect in the present invention is.

As is clear from the above description, the present invention is extremely useful for manufacturing not only a photoelectric conversion device or a light emitting element but also various semiconductor devices such as a field effect semiconductor device and a photosensor array using the same reaction tube. The present invention provides an important manufacturing apparatus and manufacturing method, whereby a single day single crystal semiconductor film can be formed on 100 to 500 substrates in the same time as when four 10 cm squares are formed by a conventional vertical plasma CVD apparatus. Can be made and is very suitable for mass production. Furthermore, by arranging the electrode structure or the substrate as in the present invention, the photoelectric conversion device having the PIN structure can be provided with a photoelectric conversion device.
The conversion efficiency of more than 100% could be repeatedly and stably obtained, and the film quality was also excellent.

In the present invention, silicon carbide (SixC
_The description is centered on _1−x 0 ≦ x <1). However, if germane is used as the reactive gas, SixGe _1-x (0 ≦ x <
1) can be obtained, and it is also possible to obtain a so-called tandem structure, in which the first PIN structure is made of silicon and silicon carbide, and the second PIN structure is made of silicon and germanium silicide.

The present invention employs the horizontal plasma CVD shown in FIG.
The device is shown as the center. However, the method of making the electrode is the dielectric type, and the plasma CV that uses arc discharge.
The present invention is effective even for the D device. The method of the present invention can be similarly applied to a vertical type and a vertical type bell jar type plasma CVD apparatus.

[Brief description of drawings]

FIG. 1 is a plasma vapor phase apparatus of the present invention.

FIG. 2 shows a part of FIG.

3 is a chart using the apparatus of FIG. 1 and a plasma vapor phase method of the method of the present invention.

FIG. 4A is another material showing the efficiency of the photoelectric conversion device obtained according to the chart of FIG. 3 and FIG. 4B is another material showing the doping prevention effect of the method of the present invention.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 12, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Etching method for carbon coating

[Claims]

Detailed Description of the Invention

[0001]

The present invention relates to the etching of carbon coatings.
Concerned.

[0002]

BACKGROUND OF THE INVENTION coating mainly containing carbon or carbon by the conventional plasma vapor phase method on a substrate provided in the reaction furnace (hereinafter
After forming a first semiconductor device having P-type and N-type semiconductor layers by a lower carbon film) , N or P-type impurities of this semiconductor device react in the P or N-type semiconductor layer to be produced next. It was re-emitted from the inner wall of the apparatus or the holder of the substrate, and it was mixed in at a concentration of 10 ¹⁵ to 10 ¹⁸ cm ^-3 .

In order to reduce the effect of this impurity oxygen doping, a patent application for semiconductor device fabrication method filed by the inventor of the present invention is 56-55608 (original display 53-1528).
87 application on December 10, 1978) is known. For example, when trying to make a PIN semiconductor device, each P
Layers, I layers, and N layers are made into independent reaction furnaces, and the substrate is moved between the layers. This method can have the same measures as those of the present invention, and can obtain extremely preferable electric characteristics. However, in that case, the apparatus is three times as much as the one-chamber system, and the manufacturing cost is 2.5 to 3 times more expensive. Further, it has a defect that it is not suitable for mass production.

[0004]

SUMMARY OF THE INVENTION The present invention is as described above.
The purpose is to prevent impurities from entering the semiconductor layer.
ing.

[0005]

[Means for Solving the Problems ]
After the semiconductor device is manufactured for the purpose, the semiconductor layers that were previously manufactured and adhered to the inner wall of the reaction device, the surface of the substrate holder and the like are removed by converting reactive gas such as CF ₄ into plasma. The purpose was to provide a process.

By doing so, the RUN-T can be reproduced with good reproducibility.
The characteristics of O-RUN can be reduced and the obtained characteristics can be made extremely excellent.

The present invention mainly describes a method of using a horizontally arranged reaction furnace or reaction cylinder (10 to 30 cmφ, length 1 to 5 m) for mass production.

An electrode for supplying electromagnetic energy for converting a pair of reactive gases into plasma is provided outside the reaction tube, and a heating device is provided outside the electrode so as to surround the reaction tube and the electrode. A reactive gas is caused to flow in the direction of the furnace, and the substrates are arranged along the flow of this gas.

Further, the substrates are arranged in the apparatus in a direction perpendicular or parallel to the electromagnetic field generated by a pair of electrodes, and the substrates are arranged in a plurality of stages or a plurality of rows to form a substrate of 2 to 20 cm.quadrature. It is mainly described that a film, particularly a silicon, carbon silicon carbide or silicon germanium, germanium film, that is, a semiconductor film mainly containing a tetravalent element, is formed at once on 400 formation surfaces of 20 rows in total.

The present invention relates to a reactive gas composed of a hydride or a halide (carbide silicide gas) having a carbon-silicon bond, a silicide gas such as silane (Si _n H _{2n + 1} n ≧ l) or acetylene. A non-single crystal silicon carbide, silicon or carbon-based coating film is formed on the surface to be formed by using a hydrocarbon at a reaction furnace pressure of 0.05 to 1 torr for 100 to 40
The present invention relates to a plasma vapor phase method for forming at a temperature of 0 ° C.

The present invention further includes an impurity gas containing trivalent impurities such as B, Al, Ga and In, such as diborane (B ₂ H ₆ ), and an impurity gas containing pentavalent impurities such as phosphine (PH). ₃ ) or arsine (A
sH ₃ ) is gradually added so that the P-type layer, the I-type layer and the N-type layer are further laminated in the order of PIN in close contact with the substrate having the surface to be formed, and this is repeated for stable production. The purpose is to Further, according to the present invention, a semiconductor having an amorphous structure (referred to as AS), semi-amorphous (semi-amorphous, hereinafter referred to as SAS) having a crystallinity of 5 to 100 Å, or 5 to 200 Å by the power of electromagnetic energy to be turned into plasma A non-single-crystal semiconductor film such as a semiconductor having a micro-polycrystal (hereinafter referred to as PC) structure having a size of 1 is produced. When stronger electromagnetic energy is applied, the substrate surface is likely to have an amorphous structure sputtered with defects. In order to eliminate such a defect structure, the substrates are separated from each other by 10 to 40 mm, typically 20 to 25 mm, and even when high energy of 200 to 500 W is required for the plasma reaction, this spice is formed on the surface to be formed. It is characterized in that it has characteristics equivalent to those obtained by controlling the distance for obtaining substantial plasma energy by the distance between the substrates and forming a film with a weak power of substantially 2 to 20 W.

Therefore, in the present invention, silicon carbide (SixC _1-x 0 <x <
When trying to make 1), a material having a carbon-silicon bond was used. That is, a hydride or halide having a carbon-silicon bond, such as tetramethylsilane (Si (CH
₃ ) ₄ ) (simply called TMS), tetraethylsilane (Si
(C ₂ H ₅ ) ₄ ), (Si (CH ₃ ) xCl _4-x (1≤x≤3)
A reactive gas such as Si (CH ₃ ) xH _4-x (1 ≦ x ≦ 3) is used to facilitate Si—C bond formation in the reaction product.

When a film containing silicon as the main component is to be obtained, Si _n H _{2n + 2} (n ≧ 1) silane, SiF ₄ or a mixed gas thereof is used. When trying to obtain carbon, acetylene (C ₂ H ₂ ) or ethylene (C
₂ H ₄ ) was mainly used. By doing so, silicon (Si), silicon carbide (SixC _1-x 0 <x <1) or carbon (C) (when these are combined, SixC _1-x (0 ≦ x
Since it can be expressed as ≦ 1), hereinafter, when referring to silicon carbide, SixC _1-x (meaning 0 ≦ x ≦ 1) is produced).

Further, a trivalent or pentavalent impurity is added here to form a P-type, an I-type (substantially true without artificially adding impurities including intrinsic or autodoping) and N-type from the surface to be formed. the semiconductive material or semi-insulating material was produced.

Further, when such a reactive gas is used, the electromagnetic energy of 50 W or less at a pressure of 1 atm or less, particularly 0.01 to 10 torr, typically 0.3 to 0.6 torr, can be applied to the reactor, for example. 0.01-100MHz
In particular, it is possible to form a coating at 500 KHz or 13.56 MHz. That is, a low energy plasma CVD apparatus could be obtained.

When a high-energy plasma atmosphere of 50 to 500 W is further applied, the formed silicon carbide is crystallized, and as a result, 0.1 to 5% of boron or phosphorus (here, (BH or PH) / (carbide gas or silicon carbide gas + silicide gas ratio) is added), the electrical conductivity was 10 ^-9 to 10 ^-3 (Ωcm) ^-1 at low energy. Is 10 ^-6
We were able to increase it to about 10 times ⁺² (Ωcm) ^-1 .

Further, the silicon carbide obtained by using this high energy method can have a so-called SAS structure having a microcrystalline structure with a size of 5 to 200 Å. In such a SAS, the ionization rate of the P or N type impurity serving as an acceptor or a donor is 97 100%,
All of the added impurities could be activated. The present invention will be described below with reference to the drawings.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the outline of a plasma CVD apparatus using the present invention. A substrate having a surface to be formed in FIG. 1 (1)
Is held by a square quartz holder, and in the drawing, it has a structure of 14 columns in 7 rows and 2 columns. The substrate and the holder are installed in advance in a separate chamber (29) in front of the reactor from an inlet (30), and a valve (32) and a rotary pump (33) perform vacuum squeezing. Further, the opening / closing door (34) is opened and introduced into the reaction furnace by an automatic feeder, and the mixing plate (35) for the mixer is also arranged at the same time. These were performed in a vacuum state in both the reaction furnace and the separate room, and efforts were made to prevent oxygen (air) from entering the reaction furnace at all. Further, by closing the opening / closing door (34), the substrate was placed between the electrodes (9) and (10) as shown in the drawing.

Each substrate is 10 to 40 mm, typically 20 to 2
The reactive gases from the holder are arranged at intervals of 5 mm, and a mixer (8) is provided in front of the reaction furnace (25) to form a laminar flow, and these reactive gases are evenly distributed in the space between the substrates. It is provided to be injected into. The formation surface is a bottom surface of the substrate or a side surface vertically arranged with the back surfaces of the substrates overlapped with each other.

Further, the drawing shows a structure in which the reaction system is seen from above, and the substrates (1) are arranged vertically with their back surfaces aligned with each other. As described above, it is extremely important to remove the flake to the lower part by utilizing gravity, considering the mass production yield. More substrate reactor was inserted to (1) (25), the electric field of the electromagnetic energy in the perpendicular or parallel to the substrate (especially when parallel easily obtained homogeneity of the coating) in FIG. 2 (A) or (B) In particular, a pair of electrodes (9) and (10) are arranged vertically or horizontally so as to be added as shown in (B). An electric furnace (5) is provided outside this electrode, and the substrate (1) is 100 to 400.
C. Typically, it is heated to 300.degree.

The reactive gas and the carrier gas for example helium hydrogen or helium from (13), from diborane a trivalent impurity (14), phosphine tetravalent from (15) is a pentavalent additives Silica gas silane as an additive was introduced from (16).

A reactive gas T having a carbon-silicon bond
When MS (20) is used, it is stored in the stainless steel container (21) because it is a liquid in the initial state. This container is controlled at a predetermined temperature by the electronic thermostatic layer (22).

This TMS has a boiling point of 25 ° C., the rotary pump (12) is evacuated through the valve (11),
0.01 to 10 torr, especially 0.02 to 0.
It was kept at 4 torr. By doing this, a pressure lower than 1 atm results in no TM
S can be vaporized. This vaporized TMS is 1
Introducing into the reaction furnace at a concentration of 00% via a flow meter enables the flow rate to be controlled more accurately than in the conventional method in which the container (21) is bubbled to release the reactive gas. , Technically important.

When the flow meter was clogged for practical use, a helium was introduced from (24) in the drawing. In addition, the reaction tube (2
5) or when removing the reaction product adhering to the inner wall or surface of the holder (2), CF ₄ or CF ₄ + O ₂ (2 to 5%) is introduced from (17), and electromagnetic energy is applied to add fluorine radicals. Was generated and vapor-phase etching was performed to remove.

Furthermore, in this plasma discharge, after the reactive gas is mixed into the mixing chamber (8), the excitation chamber (2
In 6), a spatial reaction in which decomposition or reaction was caused and a reaction product was formed on the substrate was mainly used. As the electromagnetic energy, DC or high frequency was mainly used from the power source (4).

In this way, a silicon carbide coating film was formed on the surface to be formed. For example, the substrate temperature was 300 ° C., the high-frequency energy output was 25 W, silane or TMS was 50 cc / min, and He was 250 cc / min as a carrier gas. With (reactive gas / He) 5, a film growth rate of 160Å / min could be obtained.

Further, for this film formation, a PIN junction, P
An N junction, a PI, an NI junction, a PINPIN junction, etc. were formed by gradually laminating reaction products required to have the required thickness on the substrate.

After the coating film has been formed on the surface to be formed in this manner, the reactive gas is sufficiently purged from the reaction tube, the opening / closing door (34) is opened, and the mixer mixing plate (35) is opened. , The substrate on the jig (3) is placed in a separate chamber (29) by an automatic drawing tube, and the reaction cylinder and the separate chamber are both vacuumed (0.01
(below torr) and moved. Further, after closing the opening / closing door (34), the valve was opened from (31) in another room to fill it with air to bring it to atmospheric pressure, and then the substrate having the jig and the film formed thereon was taken out.

As is clear from the above examples, according to the present invention, the reactive gas is mixed in the mixer (8) and then the exhaust port (6) is randomly moved in a layered state (microscopically in a plasmaized state). The substrate is arranged in parallel with this flow, and a film is formed on the surface to be formed to a thickness of 0.1 to 3 μ with a variation of ± 5% or less. There is.

Further, at this time, the plasma is generated by utilizing the glow discharge method, and the feature thereof is that the electrode is arranged outside the reaction tube so that the plasma is uniformly generated on a large amount of the substrates.

Further, in forming the film, as shown in the drawing, 7 steps 2
If the reaction cylinder is lengthened to 20 rows and 20 rows instead of rows, it is not 0.4 torr but 0.2, 0.1,
The lower pressure of 0.05 torr is important for obtaining the uniformity of the film quality, particularly the uniformity of the front row and the last row.

Further, in order to prevent mixing of uncontrollable oxide gas such as oxygen into the reaction cylinder, a separate chamber is provided, and it is combined with the work in the atmosphere through this separate chamber. Was very important to obtain reproducibility of.

FIG. 2 shows the relationship between the arrangement of the substrate (1) and the electrodes (9) and (10) as seen from the direction of the exhaust port (6) in the drawing of FIG. In the drawing, (A) shows the substrates arranged horizontally and the electromagnetic fields of the electrodes (9) and (10) arranged horizontally. In this case, the number of substrates that can be introduced at one time can be increased.

In FIG. 2B, the electromagnetic fields by the electrodes (9) and (10) and the substrate (1) are both vertical, and the number of substrates arranged is twice that of (A).

FIG. 3 shows an operation procedure chart of the semiconductor device manufacturing method of the present invention. "0" in the drawing
(49) is 0.01 torr due to evacuation of the reactor.
Retention below r is shown. Further, "40" of "1" indicates the plasma etching process according to the present invention.

In order to eliminate the history of the semiconductor device fabrication (40), that is, the previous run, the plasma etching process shown in (D) and (E) was performed. That is, FIG. 3 (B) shows a vacuum drawing (49) CF ₄ or CF ₄ +0 ₂ (about 5%).
Then, plasma etching (53) was carried out for 20 to 1 hour. A vacuum is further drawn, and then a hydrogen plasma treatment (5
0) for 10 to 30 minutes, and 0.05 to 0.
5μ I-type or first run semiconductor layer (4
A semiconductor layer having the same conductivity type and components as in 2) was prepared. This method was the most thorough and guaranteed reproducibility.

A simple method is shown in (E) (49).
The steps of vacuum evacuation, plasma etching (53) and removal of residual adsorption gas (50) were performed.

As a result, P or N type impurities are separated from each other () between the final step (44) of the fabrication (48) of the first semiconductor device and the first step (42) of the next step (48). It was possible to eliminate the possibility of contamination in 42). It was also possible to prevent the addition of additives such as carbon and germanium in (44) in (42).

FIG. 4 shows the result of evaluation of the effect by the method of the present invention.

FIG. 4 shows the result of a photoelectric conversion device manufactured using the method of the present invention. In this case, ITO is formed on a metal such as a stainless substrate or a glass which is a transparent substrate as a substrate.
Of 500 to 2000Å, and a substrate having a multi-layered electrode on which tin oxide or antimony oxide was formed to a thickness of 100 to 500Å. On top of this, P-type silicon carbide (SixC _1-x 0 ≦ x ≦ 1) (for example, x = 0.3 to
0.5) to a thickness of 100 to 300 Å and to this upper surface is added intrinsic or substantially intrinsic AS or SAS silicon.
N-type silicon carbide (SixC _1-x 0 ≦ x ≦ 1 such as x = 0.3 to 0.5) is formed on the upper surface to a thickness of 4 to 0.7 μm.
Was made to have a thickness of 100 to 300 Å. The specifications of the P, I and N type semiconductors are shown in FIG.
(42), (43), (44) in the chart of
(42) .....

Further, after this, in this step, 600 to ITO is added.
A photoelectric conversion device was made by forming a thickness of 800 Å or an aluminum metal film by a vacuum deposition method. The conversion efficiency is shown in FIG.

The cell size of 1 cm ² is AMl (100 m
The value of (70) was obtained when the pretreatment (40) was not added under the condition of W / cm ² ) in 3% of (71) and when the pretreatment was performed. Furthermore, the efficiency (60) of the run (every production day) changes due to the addition of the intermediate step (46), and (61) is obtained without any addition.

The efficiency of (60) can be 11 to 9%, while the efficiency of (60) is 1 to 4 when the method of the present invention is not used.
There was only%.

Further, when the cell area is 100 cm ² , the efficiency of 7 to 9% can be obtained by using the method of the present invention, and it is 0 to 3% when the method of the present invention is not used. In particular, those having no diode characteristics had 30% or more and could not be manufactured.

FIG. 4B shows the electric conductivity value when an I-type silicon semiconductor is produced especially in the process of producing a P-type semiconductor in the surface process.

When a P-type semiconductor is produced in the previous step and the pretreatment of the intermediate treatment method of the method of the present invention is not carried out, the electric conductivity by light irradiation of AM1 is (65). In some cases, the reverse of the dark conductivity (64) was observed, and the value was 10 ⁻⁶ to 10 ^−4, which was large and varied. On the other hand, when the pretreatment of the present invention was performed, photoconductivity (70) and dark conductivity (70 ') were obtained. When the intermediate treatment was performed, photoconductivity (62) and dark conductivity (63) were obtained. These clearly show how important the prevention of the doping effect in the present invention is.

In addition to this, in a semiconductor device having at least one junction, especially PIN, PI, NI or PN junction on a substrate provided in the reaction furnace, the inner wall of the reaction furnace, particularly plasma atoms or reactive gas, collides. In order to prevent the release of impurities, particularly oxygen and alkali metal atoms, from the inner wall of the inner wall, an intrinsic or substantially intrinsic semiconductor layer such as non-single-crystal silicon is previously formed on these surfaces (in this case, at the beginning of the next step). The coating produced may be coated).

In order to prevent re-emission with the coating for substantially removing them, the present invention causes the semiconductor layer to output the electromagnetic energy Po necessary for manufacturing a semiconductor device Po, for example, 5
~ 100W, temperature To, for example, 200 ~ 320 ℃,
Po-10 W (however, at least 5 W) to Po + 30 W, and To-50 ° C. to To + 50 ° C. are particularly preferably prepared under the same or substantially the same conditions as those of Po and To.
It is characterized in that it is formed to a thickness of 2-1 μ.

Regarding the conventional plasma CVD method, a semiconductor device having a PIN junction or the like has been manufactured in one reaction furnace. However, if this joining is repeated, it suffers from completely indefinite deterioration and variation, and only the reliability of the semiconductor device is unsuitable.

As a result of investigating the cause, the most probable cause is that oxygen and alkali metals adhering to the inside of the reaction furnace are mixed in the semiconductor layer and cause a decrease in electric conductivity. Even if 1PPM is mixed, the dark conductivity of 10 ^-6 (Ωcm) ^-1 is 10 ^-8 (Ωcm) ^-1 and 1/100
Had been lowered to.

Further, even in the case of alkali metal, the incorporation of 5PPM causes a decrease in the conductivity of P-type and I-type and a decrease in the conductivity of the transparent conductive film.

In order to prevent these contaminations, a semiconductor layer having a thickness of 0.2 to 2 .mu. It was very important to form and coat it. Further, for the deterioration of reproducibility characteristics, an attempt was made to form an N or P type semiconductor layer in the last step and to form a P or N type semiconductor layer in the next first step for the production of one semiconductor device. At this time, the first impurities such as phosphorus are mixed in the P-type semiconductor at a concentration of 10 ¹⁵ to 10 ¹⁸ cm ⁻³ . Therefore, P
For example, even if the p-type layer is formed by adding boron to a concentration of 10 ¹⁸ to 10 ²¹ cm ⁻³ , the electric conductivity of the p-type semiconductor layer is extremely poor because the recombination centers increase due to the incorporation of phosphorus.
When there is no mixture, 10 ^-2 to 10 ⁺¹ (Ωcm) ^-1 against 10
Only ^-6 to 10 ^-4 (Ωcm) ^-1 and 1/100 to 1/1000 were obtained.

Therefore, in the PIN photoelectric conversion device, an efficiency of 2 to 4% was obtained only with a variation of ± 200% for each run, which was not preferable. However, according to the method of the present invention, it has become possible to obtain a high conversion efficiency of about 3 to 5 times that of 8 to 10%.

In FIG. 3 (A), "40" of "1" indicates the coating of silicon or silicon carbide on the reaction furnace or reaction cylinder and holder according to the present invention. This coating is shown in detail in FIGS. 3 (B) and 3 (C). Figure 3
(B) is set to 0.01 torr or less by vacuuming (49), and is held for 10 to 30 minutes, and then hydrogen is subjected to plasma cleaning with electromagnetic energy for 30 minutes to 30 W, and adsorption, moisture, and oxygen are removed. Removed. After the hydrogen was further removed, the helium was simultaneously turned into plasma by the output of 30 to 50 W for 10 to 30 minutes by (51) to further remove the hydrogen on the surface. For this hydrogen plasma generation (50), the hydrogen is generated at a concentration of 1-5% in hydrogen.
When 1 or Cl is added, chlorine radicals are simultaneously generated, and this radical has an effect of sucking out an alkali metal such as sodium existing inside the holder such as quartz. Therefore, the concentration of sodium, water, oxygen, etc. at the background level can be reduced to 10 ¹⁴ cm ^-3 or less in the formed film, which is a very important pretreatment step.

When this chlorine was added, it was also effective to remove the chlorine adsorbed on the wall surface by sputtering with the inert gas (51).

Thereafter, these systems are evacuated, and then silane, which is a silicide gas, or TMS, which is a silicon carbide, is introduced and decomposed by plasma energy to obtain 0.1 to 2 μm.
The thickness is typically 0.2 to 0.5 μ. When these films are formed, the region where high electromagnetic energy is applied, that is, the region where impurities are likely to be re-emitted, is particularly thick and easy to stick, which gives doubly preferable results.

Even when the complicated pretreatment process of the present invention is not performed, after vacuuming as shown in FIG.
Silicon or silicon carbide in (52) is also 0.1 to
It was effective to form 2μ and prevent the re-release of oxygen and alkali metal from the reactor wall.

Further, in FIG. 3A, for manufacturing a semiconductor device, substrate coating, system vacuuming (41), P or N type semiconductor manufacturing (42), I type semiconductor layer manufacturing (43). , Manufacturing an N-type semiconductor layer (44),
A first semiconductor device was produced (48). It goes without saying that this semiconductor device must be manufactured according to a device design specification having at least one junction such as PI, NI, PIN, PN.

After this, the same semiconductor as the I-type semiconductor layer shown in (46) or the semiconductor layer shown in (42) is added to this system only for the reaction furnace or for the reaction system in which the reaction furnace and the holder are inserted and installed. The layer coating was such that the debris from step (44) used in the previous fabrication of the semiconductor device did not affect the next run. The details are shown in FIGS. 3 (B), (C), (D), and (E).

That is, as shown in FIG. 3B, a semiconductor layer is formed in the first step of vacuum drawing (49) hydrogen plasma discharge (50), helium plasma processing (51), and semiconductor device run as in the above-mentioned pretreatment. It has a process (52). However, these (50) and (51) are already (46) in (A)
Therefore, it is generally sufficient to form a semiconductor layer having a thickness of 0.1 to 2 μm in (52) of (C).

[0061]

As is apparent from the above description, the present invention can be applied to not only a photoelectric conversion device or a light emitting element but also various semiconductor devices such as a field effect semiconductor device and a photosensor array using the same reaction tube. This is an extremely important manufacturing apparatus and manufacturing method, which allows the production of 100 single crystals per day on 100 to 500 substrates in the same time as the production of four 10 cm □ by a conventional vertical plasma CVD device. A semiconductor film can be formed, and it is suitable for extremely high volume production.
Further, by arranging the electrode structure or the substrate as in the present invention, the photoelectric conversion device having the PIN structure is
A conversion efficiency of 0% or more could be repeatedly and stably obtained, and the film quality was also excellent.

In the present invention, silicon carbide (SixC
_The description is centered on _1−x 0 ≦ x <1). However, if germane is used as the reactive gas, SixGe _1-x (0 ≦ x <
1) can be obtained, and it is also possible to obtain a so-called tandem structure, in which the first PIN structure is made of silicon and silicon carbide, and the second PIN structure is made of silicon and germanium silicide.

The present invention is the horizontal plasma CVD shown in FIG.
The device is shown as the center. However, the method of making the electrode is the dielectric type, and the plasma CV that uses arc discharge.
The present invention is effective even for the D device. The method of the present invention can be similarly applied to a vertical type and a vertical type bell jar type plasma CVD apparatus.

The present invention is particularly effective in a horizontal reactor. In addition, it is particularly effective when trying to make a large number of semiconductor devices on a substrate, and the manufacturing cost including the depreciation of the device per semiconductor device is 1 /
It has a great feature that it can be 100.

[Brief description of drawings]

FIG. 1 is a plasma vapor phase apparatus of the present invention.

FIG. 2 shows a part of FIG.

3 is a chart using the apparatus of FIG. 1 and a plasma vapor phase method of the method of the present invention.

FIG. 4A is another material showing the efficiency of the photoelectric conversion device obtained according to the chart of FIG. 3 and FIG. 4B is another material showing the doping prevention effect of the method of the present invention.

Claims (1)

Claim: What is claimed is: 1. A method for etching a carbon coating, which comprises plasma etching a carbon film with a fluoride gas.