JPS5941464A - Apparatus for forming film - Google Patents

Abstract

PURPOSE:To make it possible to perform the formation of a uniform film within a short film forming time, by a method wherein a container for exciting an additive and a reaction container for decomposing stock gas are separately provided and a means for introducing the excited additive into the reaction container is provided. CONSTITUTION:Gas containing fluorine or the like is introduced into an exciting apparatus 2 and glow discharge is generated between opposed electrodes 26, 27 to decompose the gas to form an exiting state. On the other hand, stock gas such as silane gas or the like is emitted into the reaction chamber 5 of a reaction apparatus 1 from an emitting pipe 12 to generate glow discharge between the emitting pipe 12 and a substrate 6. By this method, the stock gas is decomposed to generate various radicals. The gas excited in the exciting apparatus 2 is introduced into a reaction chamber 5 from a conduit 30 and reacted with the stock gas to form an amorphous silicon film having fluorine, hydrogen or the like added thereto on the surface of the substrate 6. By this apparatus, a film forming time can be shortened without lowering film characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a film forming apparatus for decomposing a raw material gas and forming a film containing an element contained in the raw material gas on a substrate.

Technical background of the invention and its problems Conventionally, inductively coupled or capacitively coupled plasma CVD apparatus (chemi-cal vapor CVD) has been used as an apparatus for forming a film by decomposing source gas by electric discharge under low pressure.
This method involves introducing a raw material gas into a reaction chamber under reduced pressure, and applying a high-frequency wave between a high-frequency coil provided surrounding the reaction chamber or opposing electrodes provided in a pressure reaction chamber. Electric power is supplied to discharge and decompose the raw material gas in the reaction chamber to generate plasma, thereby forming a film containing the elements in the raw material gas on a substrate placed in the reaction chamber.

In this way, using a plasma CVD apparatus, for example, a silicon-containing gas is subjected to discharge decomposition to form an amorphous silicon film over a wide area, and this film is used as a photoreceptor. has been proposed recently. The most common source gas containing silicon is 7rane (SiH41), but when silane is decomposed by discharge, a large number of ions and radicals are generated. Of these, the important ones for forming an amorphous silicon film are: Among the excited species, there is a SiH2 radical.It is thought that this SiH2 is converted to 5iHn (n=0, 1.2) and an amorphous silicon film containing hydrogen is deposited on the substrate.

When forming an amorphous silicon film using such an apparatus, a considerable amount of film forming time is required, especially in order to form a uniform film over a wide area.

This is because SiH2 as an excited species generated by discharging silane reacts with H and returns to silane, and H in the same excited state forms 5iHn in the amorphous silicon film deposited on the substrate. This may cause the film to react and return to SiH4 (etching phenomenon), resulting in a decrease in the film formation rate.For this reason, it is possible to increase the high frequency power used for glow discharge in order to increase the film formation speed, but it is possible to simply It is not possible to form a uniform film over a wide area or to form a high-quality film by simply increasing the high-frequency power. The purpose is to provide a film forming apparatus that can perform film formation in a short time.

Summary of the Invention The present invention is a method for decomposing a raw material gas in a reaction chamber to form a film containing elements contained in the raw material gas on a substrate, and for introducing an additive in an excited state in advance into the reaction chamber. This process forms a film.

As a result, the time required to pre-excite the additive is not included in the reaction time for film formation, so that the film formation rate is not reduced. Furthermore, since the introduced additive is in an excited state in advance, the reaction efficiency with the decomposed raw material gas is increased.

Furthermore, in the present invention, a container for decomposing the additive gas into an excited state and a container for decomposing the source gas are provided separately, and the additive excited in the former container is introduced into the latter container to form a film. It is something.

Therefore, by decomposing the additive gas, the influence on the formed film can be reduced, and the film forming time can be shortened.

That is, when decomposing additive gas, it is common to use, for example, glow discharge. Although the light produced in this case has an adverse effect on the formed film, such an adverse effect can be reduced by decomposing the additive gas in a separate room. Furthermore, by decomposing the additive gas in a separate chamber, it is possible to completely decompose the gas and excite the additive, which increases the reaction efficiency and, as a result, increases the film formation rate. In a method that forms a silicon-containing film on a substrate by decomposing a raw material gas containing at least silicon and hydrogen, substances that are likely to bond with hydrogen produced by decomposing the raw material gas are excited in advance and placed in the reaction chamber. By introducing it, a reaction is caused.

Therefore, it is possible to prevent a reverse reaction or an etching phenomenon from occurring due to hydrogen generated by decomposition, and the film formation rate can be significantly increased.

Embodiment of the Invention Referring to FIG. 1, a schematic vertical cross-sectional view shows a film forming apparatus according to the present invention. This device is broadly divided into a reaction device 1 and an excitation device 2.

The reactor 1 has a casing 4 provided on a base 3. Inside the casing 4, a sealed reaction chamber 5 is formed. A substrate 6 is held within this reaction chamber 5 . The base body 6 was, for example, a drum-shaped body made of aluminum, and had a diameter of 130 mm and an axial length of 289 mm.

The base body 6 is placed on a rotatable holding table 7. The reaction chamber 5 is connected to the reaction chamber 5 via the holding table 7id and the bearing 8 provided on the base 3.
It has an outwardly protruding portion, to which a motor 11 is connected via a gear 9.10. Therefore, the rotation of the motor 11 is transmitted to the holding table 7 via the gears 9 and 10, causing it to rotate, resulting in the base body 6 being constantly rotated. A pipe 12 is provided, and this discharge pipe 12 is connected to the inlet pipe 1 outside the casing 4.
The 0 introduction pipe 13 connected to the
The cylinders 16, 17 are connected via 5. The cylinder 16 contains silane (SiH4) as a source gas. The cylinder 17 also contains a gas to be mixed with the silane gas as needed. For example, GeH
4,1,,5nC44, CH41C2H4, C2H6, etc. are used. G e H4+ S n Ct
4 is a part of Si in the formed silicon-containing film.
OG is introduced for the purpose of increasing the sensitivity of the formed film to long-wavelength light by substituting e or Sn to obtain an electrophotographic photoreceptor that can respond to, for example, laser light.
H4 and C2H41C2H6 are introduced for the purpose of increasing the optical energy gap of the formed amorphous silicon film, and a portion of Si is replaced with C.

Although silane (SiH4)e is used as the raw material gas, commercially available silanes such as disilane may also be used.

On the other hand, one exhaust pipe is provided from the base 3 through a communication hole 18'z, and this exhaust pipe 19 is connected to an exhaust pump 20.

In fact, the discharge pipe 12 also acts as a counter electrode, to which a high frequency power source 21 is connected. Further, the base body 6 is grounded via a holding table 7 and constitutes a counter electrode with the discharge pipe 12. Therefore, the reaction apparatus 1 shown in FIG. 1 constitutes a capacitively coupled plasma CVD apparatus.

Next, the excitation device 2 has a casing 23 provided on a base 22 . The pressure inside the casing 23 is reduced by an exhaust pipe 24 and an exhaust pump 25. Moreover, the zero electrode 26, which has counter electrodes 26 and 27 provided inside the casing 23, is connected to a high frequency power source 28, and the electrode 27 is grounded. Furthermore, the casing 23 has an introduction pipe 2.
9.30 is provided. The introduction pipe 29 is connected to the pulp 31
A cylinder 32 is connected via the cylinder. The cylinder 32 contains an impurity gas to be doped into the film to be formed or an additive gas for improving the film formation rate. This gas includes B2H6+ PH3, AsH31021N
2+N20+NH3+ F 21 S iHF a +
S i F 4 + ozone, H20□ may be used. B2H6 is used to make an amorphous silicon film similar to an N-type semiconductor into an earthy-smelling semiconductor by doping the formed film with Bffiff. PH3,
AsH3 is also used to make it an N-type semiconductor by doping it as a P or As k impurity.

Also, 02°N21 N20. NH31F2. Si
HF3. SiF++ ozone H2O2 is oxygen (0),
It is used to increase the optical energy gap of the formed amorphous silicon film by adding nitrogen (I) or fluorine (Fl).
) Gases containing F or Ok (The binding energy of the compound HF is 135 Kcal/mol
, the binding energy of compound H20 is 119.5 Kc
(at/mo 1, all of which are stable compounds) were used.

The introduction pipe 30 carries oxygen excited within the casing 23 (0
) or fluorine) to the reactor 1.

Note that the excitation device 2 shown in FIG. 1 emits glow 1! F 21 S t HF a
+ S I F 4+ 021 Ozone and H2O2 can be decomposed into an excited state.

Furthermore, in addition to the above-mentioned cylinder 32, another cylinder is connected to the introduction pipe 29 (not shown), and this cylinder is filled with the impurity gas (B2Hs+PHa) described above.

(AsHa, N2, N201NHa, etc.) can be stored in the casing 23 and introduced into the casing 23 together with the additive gas, brought into an excited state together with the additives, and introduced into the reaction chamber 5. In this case, in addition to the effect of speeding up film formation due to the additive, the effect of impurity doping (the formed film
type, P type or intrinsic semiconductor).

Next, the operation of the film forming apparatus configured as described above will be explained.

First, the pulp 31 is opened and a gas containing fluorine (for example, F2) is introduced from the cylinder 32 into the casing 23 through the introduction pipe 29. At this time, the high frequency power supply 28 is operated to generate glow discharge between the opposing electrodes 26 and 27.

This generates plasma, and the F inside the casing 23
2 gases are decomposed and fluorine ■ is brought into an excited state 〇 On the other hand,
The pulp 14 is opened and the silane gas contained in the cylinder 16 is sent to the inlet pipe (here, pure silane 100% e was used as the raw material gas), and the raw material gas is discharged from the discharge pipe 12. Then, when a high frequency power source 21 is applied between the discharge tube 12 and the base 6, a glow discharge is generated and plasma is generated. As a result, the raw material gas in the reaction chamber 5 is decomposed and various radicals are generated. Note that the inside of the casing 23 and the inside of the reaction chamber 5 are evacuated and depressurized by the exhaust pumps 20 and 25.

Further, the base body 6 within the reaction chamber 5 is always rotated in a fixed direction by a motor 11.

Further, 33 is a heater that maintains the temperature of the base 6 at a predetermined value.

Now, the fluorine excited in the excitation device 2 is introduced into the reaction chamber 5 through the introduction pipe 30.

Therefore, fluorine in the excited state and the decomposed source gas react in the reaction chamber 5, and the surface of the substrate 6 has Si:F
An amorphous silicon film is formed which is mainly composed of silicon having a structure of :H and to which fluorine and hydrogen are added. In addition, excited hydrogen generated by decomposition of the raw material gas in the reaction vessel 5 combines with excited fluorine to form stable HF', thereby preventing the reverse reaction of silane and etching phenomenon.

Note that if a gas containing oxygen is used as the additive gas, S
An amorphous silicon film doped with oxygen and hydrogen having a configuration of 1:O:H is formed on the surface of the substrate 6, and hydrogen in an excited state combines with oxygen in an excited state to form stable H20.
is generated. Since the generated HF and H2O are discharged to the outside of the reaction chamber 5 from the exhaust pipe 19, there is little amount of chroma to be applied to the formed film.

In the above example, "addition" means that even if the additive is incorporated into the resulting film, the semiconductor properties of the film (
(for example, to make the film an N-type or P-type semiconductor), it means that the additive is added for the purpose of, for example, increasing the optical energy gap of the film. .

Furthermore, "doping" or "doping" means replacing a part of silicon, which is the main constituent material of a film, with an impurity for the purpose of changing the semiconductor properties of the film (for example, making it an N-type or P-type semiconductor). ing.

Therefore, in the above example, B2H6, PH3, and As1a are impurity gases for doping impurities, and the others are additive gases.

(Example) When a film was formed using the film forming apparatus shown in FIG. 1 under the following conditions, a film forming rate as shown in FIG. 2 was obtained.

○ Raw material gas: Silane (SiH4) Q Flow rate of raw material gas: 150 SCCM ○ Temperature of substrate 6: 250°C ○ Pressure inside reaction chamber 5: 0.2 to 0.4 TorrO high frequency Power supply...Frequency 13.56 MHz, 30W○
Impurity gas...Fluorine gas (F2) ○Flow rate of impurity gas...0 to 30 SCCM Figure 2 plots the flow rate of F2 (SCCM) on the horizontal axis, and the amount formed on the surface of the base 6 on the vertical axis. Film deposition rate (μm/H u
r ) is plotted.

As is clear from Figure 2, if F2 is not introduced,
That is, while the film formation rate when excited state fluorine is not introduced into the reaction chamber 5 is about 2 μm/H, F2
When the flow rate is 30 SCCM, the deposition rate is 3.7 μm/
Increased to Hfi degrees.

The amorphous silicon film formed in this way is
It can be used in electrophotographic photoreceptors, solar cells, and other applications.

Effects of the Invention As described above, according to the present invention, the film formation time can be shortened without deteriorating the characteristics (uniformity, etc.) of the formed film.

Particularly when a gas containing silicon and hydrogen is used as the raw material gas, by introducing fluorine or oxygen, which easily bonds with hydrogen, into the reaction chamber in an excited state, problems such as reverse reactions and etching phenomena do not occur.

Furthermore, since the impurities are brought into an excited state beforehand and introduced into the reaction chamber, reaction efficiency is increased and there is no risk of adverse effects on film formation.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram for explaining the deposition rate of a film formed on the same side. DESCRIPTION OF SYMBOLS 1... Reactor, 2... Excitation device, 4... Casing, 5... Reaction chamber, 6... Substrate, 21... High frequency power supply, 23... Casing, 28... High frequency power supply, 30... introduction tube. Procedural amendment (voluntary) 81 Plan, West 8 Director General of the Japan Patent Office 1, Case indication Japanese Patent Application No. 57-149199 2, Name of the invention Film forming device 3, Person making the amendment 4, Agent 〒100 1-1-6 Uchisaiwai-cho, Chiyoda-ku, Tokyo Contents of amendments to the Scope of Claims column and Detailed Description of the Invention column 6 of the specification (1) Percentage The scope of the claims will be corrected as shown in the attached sheet. (2) "Mold type or capacitively coupled type..." on page 5, line 4 of the specification.
・" should be corrected to ``Mold or capacitive coupling type...''. (3) “-depo-sitio” on page 5, line 5 of the specification
n...” is [...depositionJ
0 (4) On page 6, line 9 of the specification, "...silane is decomposed by electrical discharge..." is replaced with "...silane is decomposed by electrical discharge..."
I am corrected. (5) On page 10, line 15 of the specification, “... some G of Si
e or... 1 means 1... a part of Si is Ge
Or…” I am corrected. (6) “...GH4+C” on page 10, line 19 of the specification
2H41C2H6...” is [...CH4+
C2H4+C2H6...'' is corrected. Claims (1) Decompose the raw material gas in the reaction chamber to form a film containing the elements contained in the raw material residue on the substrate E, and generate additives in an excited state in advance. An excitation means, an introduction means for introducing the additive excited by the excitation means into the reaction chamber, and an additive substance in an excited state introduced by the introduction means and the decomposed raw material residue to react with each other. A film forming apparatus characterized in that the substrate E is equipped with reaction means for forming a film containing elements contained in the source gas. 1 Random (2) The film forming apparatus according to claim 1, wherein the raw material waste contains a Th element, and the film forming apparatus according to claim 1 is characterized in that the raw material waste is dissolved in a ratio of 1 = 1 to form a film in which ≠ element. . (3) The film forming apparatus according to claim 1 or 2, characterized in that excited fluorine or oxygen is used as the additive. (4) Excited fluorine as an additive is li”2.Si
4. The film forming apparatus according to claim 3, wherein the film is produced by decomposing either HF3 or SiF4. (5) Excited oxygen as an additive is 02. 3. A film forming apparatus according to claim 3, characterized in that the film is produced by decomposition of ozone or l-1202. (6) Claim 1, characterized in that the decomposition of raw material waste or the excitation of additives is performed by glow discharge.
The film forming apparatus according to any one of Items 3 to 3Q. (A film forming apparatus according to any one of claims 1 to 6 (c) characterized in that an impurity to be doped into the formed film is roughly introduced into the force reaction chamber. ) A self-mounted film forming apparatus according to claim 7, characterized in that one of B, P, As, or N is used as an impurity. A first container that contains a source gas and maintains it in a reduced pressure state, and a decomposition means that decomposes the source gas contained in the first container. , A second container which is provided separately from the container described in L description 1 and contains cold material waste, and an additive gas contained in this second container is decomposed and the additive gas is brought into an excited state. an excitation means for producing an additive, an introduction means for introducing the additive excited by the excitation means into the container described in F description 1, and decomposition of the excited additive introduced by the introduction means in the container described in E description 1. A film forming apparatus d characterized in that it is equipped with a reaction means for forming a film on the substrate E by reacting the raw material gas with The film forming apparatus according to claim 9, wherein the silicon Uυ raw material gas contains + element and the formed film contains silicon pod element.
The film forming apparatus according to item 1 or item 10. (12) Film formation according to claim 11, characterized in that oxygen or fluorine is used as the additive=Minato 1baQ 13) A substrate is formed by silicidizing a raw material gas containing at least sulfuric acid and hydrogen. There is a decomposition means that decomposes the raw material residue in the reaction chamber, forming a film containing sand≠element on top, and a decomposition means that excites substances that easily bond with hydrogen decomposed by the decomposition means in the reaction chamber ( (A reaction means for forming a film by causing the substance in an excited state introduced by the introduction means to react with the raw material gas E in the reaction chamber to form a film. 11. The film forming device according to claim 11, wherein the substance in the excitation state is oxygen or fluorine.

Claims (1)

[Claims] (1) In a device that decomposes a raw material gas in a reaction chamber to form a film containing elements contained in the raw material gas on a substrate, an excitation means that generates an additive in an excited state in advance; an introduction means for introducing the additive excited by the excitation means into the reaction chamber; and an introduction means for causing the additive in an excited state introduced by the introduction means to react with the decomposed raw material gas to deposit the raw material gas on the substrate. 1. A film forming apparatus comprising a reaction means for forming a film containing an element contained in. (2) The film forming apparatus according to claim 1, wherein the raw material gas contains silicon, and the film containing silicon is formed by decomposing the raw material gas. (3) The film forming apparatus according to claim 1 or 2, characterized in that excited fluorine or oxygen is used as an additive. (4) Excited fluorine as an additive is p2,5iHF
4. The film forming apparatus according to claim 3, wherein the film is produced by decomposing either a or SiF4. (5) Excited oxygen as an additive is 02. 4. The film forming apparatus according to claim 3, wherein the film is produced by decomposing ozone or H2O2. (6) Claim 1, characterized in that the decomposition of the raw material gas or the excitation of the additive is performed by glow discharge.
The film forming apparatus according to any one of items 1 to 3. (The film forming apparatus according to any one of claims 1 to 6, characterized in that an impurity to be doped into the formed film is further introduced into the reaction chamber. (8) As an impurity. The film forming apparatus according to claim 7, characterized in that any one of B, P, AS, or 1 dN is used. (9) The source gas is decomposed and the elements contained in the source gas are transferred onto the substrate. A first container that contains a raw material gas and maintains it in a reduced pressure state, a decomposition means that decomposes the raw material gas contained in the first container, and the first container a second container provided separately from the container and containing an additive gas; an excitation means for decomposing the additive gas contained in the second container to produce an additive in an excited state; introducing means for introducing the additive excited by the means into the first container; and reacting the excited additive introduced by the introducing means with the raw material gas decomposed in the first container. A film forming apparatus comprising a reaction means for forming a film on the substrate. (10) A glow discharge is used as the decomposition means or the excitation means. (11) The film forming apparatus according to claim 9 or 10, characterized in that the source gas contains silicon and the formed film contains this silicon. (12) Addition The film forming apparatus according to claim 11, characterized in that oxygen or fluorine is used as the substance.α3) A film forming apparatus that decomposes a source gas containing at least silicon and hydrogen to form a film containing silicon on a substrate. , a decomposition means for decomposing the raw material gas in the reaction chamber, an introduction means for introducing into the reaction chamber a substance that easily bonds with the hydrogen decomposed by the decomposition means in an excited state, and a hydrogen gas introduced by the introduction means. A film forming apparatus comprising a reaction means for causing a substance in an excited state and the source gas to react in the reaction chamber to form a film containing silicon. α4) The pattern forming apparatus according to claim 11, wherein the excited state substance is oxygen or fluorine.