JP4906822B2 - Thin film forming apparatus and thin film forming method - Google Patents

Description

  The present invention relates to a thin film forming apparatus and a thin film forming method for forming a microcrystalline silicon thin film.

Conventionally, an intrinsic (i-type) microcrystalline silicon thin film has been widely used as a photoelectric conversion layer of a silicon thin film solar cell. As a method for producing the microcrystalline silicon thin film, it is generally deposited on a substrate by a plasma CVD (Chemical Vapor Deposition) method using a mixed gas of silane (SiH ₄ ) and hydrogen (H ₂ ).

A conventional example of a method for producing a microcrystalline silicon thin film by this plasma CVD method will be described. A substrate stage that heats and holds the substrate in the vacuum vessel and is grounded, and a plasma electrode that is electrically connected to the high-frequency power source are arranged with their electrode surfaces parallel to each other. After the substrate is held on the substrate stage, a mixed gas of silane gas and hydrogen gas is supplied to the plasma electrode while heating the substrate to 150 to 250 ° C. The supplied mixed gas is introduced into the vacuum vessel from the gas supply hole of the gas shower head provided in the plasma electrode. At this time, when high-frequency power is supplied from the high-frequency power source to the plasma electrode, a mixed plasma of SiH ₄ / H ₂ is generated by discharge. The generated plasma generates chemically active atomic molecules such as SiH ₃ , SiH ₂ , SiH, Si, H, etc., and these particles are incident on and adhered to the substrate, thereby becoming amorphous or crystalline. A silicon thin film is deposited (see, for example, Patent Document 1).

In order to deposit a microcrystalline silicon thin film by such a plasma CVD method, a film forming method called “high pressure depletion method” is widely used (for example, see Patent Document 2). Specifically, under a high pressure, the silane gas flow rate [SiH ₄ ] is made sufficiently small (in other words, the hydrogen gas flow rate [H ₂ ] is made sufficiently large), and the silane gas flow rate ratio is set to [SiH ₄ ] / ([SiH ₄ ] + [H ₂ ]) = 1-5%, and by depleting the silane gas in the plasma, it becomes possible to deposit a microcrystalline silicon thin film. The film becomes amorphous). As a result of applying the microcrystalline silicon thin film obtained by this method to a photoelectric conversion layer of a solar cell and evaluating a prototype of a solar cell, a practical characteristic of a photoelectric conversion efficiency of about 9% is obtained.

Japanese Patent Laid-Open No. 2002-237459 JP 2001-237187 A JP-A-11-330520

  By the way, the light absorption coefficient of the i-type microcrystalline silicon thin film is smaller than that of the amorphous silicon thin film. Needs to be at least 2 μm thick. Therefore, from the viewpoint of productivity, a technique for depositing a microcrystalline silicon thin film at high speed is required. Specifically, it is ideal that a microcrystalline silicon thin film having a thickness of 2.5 μm can be deposited in a time of about 5 minutes, and in order to realize this, a deposition rate of 8.3 nm / s or more is required. Become.

However, in the method for depositing a microcrystalline silicon thin film by the plasma CVD method described in Patent Document 2, the silane gas flow rate ratio in the mixed gas of silane gas / hydrogen gas, that is, [SiH ₄ ] / ([SiH ₄ ] + [H ₂ ]. Therefore, the crystallinity of the film and the deposition rate are in a trade-off relationship. That is, when an amorphous film is formed, a large deposition rate can be easily obtained. However, when the silane gas flow rate ratio is lowered for crystallization, the deposition rate is greatly reduced, and is usually about 1 nm / s. There was a problem that. Therefore, for example, if a microcrystalline silicon thin film of 2.5 μm is to be deposited, a processing time of 40 minutes or longer is required.

Therefore, conventionally, for the purpose of increasing the deposition rate, the high-frequency power is increased and a microcrystalline silicon thin film is manufactured by the plasma CVD method (see, for example, Patent Document 3). However, since silane gas is easily dissociated by electron collision in the plasma, if the high-frequency power is increased to increase the electron density of the plasma, a large amount of SiH ₂ , SiH, Si is generated, and particles are generated in the gas phase. Occurs, and a silicon thin film having many defects is formed.

  As described above, in the conventional plasma CVD method, a microcrystalline silicon thin film with good crystallinity cannot be formed at a deposition rate of about 8.3 nm / s, and the manufacturing process of a photoelectric conversion device such as a solar cell is not possible. It has been difficult to improve the throughput and hinder cost reduction.

  The present invention has been made in view of the above, and is capable of forming a thin film capable of increasing the deposition rate while maintaining good crystallinity equivalent to that of a microcrystalline silicon thin film manufactured by a conventional high pressure depletion method. An object is to obtain an apparatus and a thin film forming method.

In order to achieve the above object, a thin film forming apparatus according to the present invention is provided with a substrate stage and a plasma electrode facing each other in a film forming chamber, supplying a silane gas and a hydrogen gas to the plasma electrode and generating a high-frequency voltage. In a thin film forming apparatus for generating plasma by applying plasma to form a microcrystalline silicon thin film on a substrate held on the substrate stage, the silane gas supplied to the plasma electrode from outside the film forming chamber is applied to the substrate A silane gas supply means that is blown to the substrate, and the hydrogen gas supplied to the plasma electrode from the outside of the film forming chamber is converted into hydrogen plasma so as to come into contact with the silane gas blown from the silane gas supply means. by blown, and a hydrogen gas supply means for plasma the silane gas, the silane gas supply means, contact A silane gas storage chamber for storing the silane gas supplied from the outside at a potential, and a plurality of cylindrical silane gas outlets provided on the substrate stage side of the silane gas storage chamber for blowing the silane gas to the substrate stage side And the hydrogen gas supply means comprises a conductive plate-like member having an opening corresponding to the formation position of the silane gas blow-out opening, and the silane gas blow-off means is not in contact with the silane gas supply means. An electrode plate that is extrapolated to the mouth and to which a high frequency voltage is applied, and the hydrogen gas supplied from the outside passes through the side surface of the silane gas storage chamber to the space between the electrode plate and the silane gas storage chamber It characterized Rukoto to have a, a hydrogen gas flow path.

According to this invention, when the silane gas and the hydrogen gas are supplied to the film forming chamber to deposit the microcrystalline silicon thin film on the substrate, the silane gas and the hydrogen gas are supplied in a spatially separated manner. Generation of SiH ₃ radicals necessary for the deposition of a quality silicon thin film and generation of H atoms necessary for the formation of a microcrystalline silicon thin film can be performed independently, and deposition and crystallization of a desired silicon thin film can be realized. As a result, the microcrystalline silicon thin film can be deposited even under the condition of a high flow rate ratio of silane gas, which can be obtained only by an amorphous silicon thin film by the conventional method. Thus, the throughput of the manufacturing process of the silicon thin film solar cell can be improved.

  Exemplary embodiments of a thin film forming apparatus and a thin film forming method according to the present invention will be explained below in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a diagram showing an example of a schematic configuration of a thin film forming apparatus according to this embodiment. This thin film forming apparatus includes a substrate stage 11 that holds a substrate 100 that is a thin film formation target, and a plasma electrode 12 in which an electrode surface is disposed in parallel with the substrate holding surface of the substrate stage 11 in a film forming chamber 10. Prepare. Here, the substrate stage 11 is grounded and disposed below the film forming chamber 10, and the plasma electrode 12 is disposed above the substrate stage 11 and connected to a high-frequency power source 14. At the time of film formation, a high frequency voltage is applied to the plasma electrode 12, and a plasma 200 is generated between the substrate stage 11 and the plasma electrode 12.

  The film forming chamber 10 has a gas exhaust port 13 for exhausting the gas in the film forming chamber 10 to the outside by a vacuum pump (not shown), and a silane gas supply port 21 for supplying silane gas to the plasma electrode 12 in the film forming chamber 10. And a hydrogen gas supply port 31 for supplying hydrogen gas to the plasma electrode 12 in the film forming chamber 10 is provided.

  A silane reservoir (not shown) for storing silane is connected to the silane gas supply port 21 by a silane gas supply line 22, and a mass flow controller 23 for controlling the flow rate of the silane gas is provided in the middle of the silane gas supply line 22. ing. A hydrogen gas storage unit (not shown) that stores hydrogen gas is connected to the hydrogen gas supply port 31 by a hydrogen gas supply line 32, and the flow rate of hydrogen gas is controlled in the middle of the hydrogen gas supply line 32. A mass flow controller 33 is provided. Thus, in this embodiment, the silane gas and the hydrogen gas are separately supplied to the plasma electrode 12 in the film forming chamber 10.

  FIGS. 2-1 to 2-3 are diagrams schematically showing an example of a detailed structure near the plasma electrode, FIG. 2-1 is a top view of the plasma electrode, and FIG. It is a bottom view of an electrode, and FIG. 2-3 is AA sectional drawing of FIGS. 2-1 and FIGS. 2-2. The plasma electrode 12 includes a silane gas storage supply chamber 120 which is a silane gas supply means formed so that silane gas can be sprayed uniformly on the entire surface of the substrate 100 held by the substrate stage 11, and a silane gas storage supply chamber 120. A hydrogen gas supply unit 130 that is a hydrogen gas supply unit that transmits the hydrogen gas in a plasma state to the vicinity of the silane gas outlet 122 below the silane gas storage supply chamber 120 at a lower portion of the film formation chamber 10. Is supported and fixed to a grounding plate 110 provided on the upper side.

  The silane gas storage supply chamber 120 is made of a conductive material and has a silane gas storage part 121 that is a space in which silane gas can be stored. In the example of this figure, the upper part of the silane gas storage / supply chamber 120 is shared with the ground plate 110, whereby the silane gas storage / supply chamber 120 is fixed to the ground plate 110.

  A silane gas supply port 21 connected to the silane gas supply line 22 is provided in the upper part of the silane gas storage supply chamber 120, and silane gas is uniformly blown to the substrate stage 11 side in the lower part of the silane gas storage supply chamber 120. A plurality of silane gas outlets 122 are provided. The silane gas outlet 122 has a cylindrical structure that projects outward from the lower surface of the silane gas storage supply chamber 120.

  A hydrogen gas supply unit 130 is provided outside the side surface 123 and the lower surface 124 of the silane gas storage supply chamber 120. The hydrogen gas supply unit 130 is disposed so as not to come into contact with the silane gas storage supply chamber 120, and includes an electrode plate 131 connected to the high frequency power supply 14 and a support member made of an insulating material that supports the electrode plate 131 on the ground plate 110. 151. In the example of this figure, a plate-like electrode plate 131 having a disk shape is disposed at a predetermined interval below the silane gas storage supply chamber 120, and is provided at the silane gas outlet 122 of the silane gas storage supply chamber 120. An opening 132 larger than the outer diameter of the silane gas outlet 122 is formed at the corresponding position, and the silane gas outlet 122 is inserted into the opening 132 so as not to come into contact therewith. Specifically, the electrode plate 131 is attached so that the opening 132 is disposed coaxially with the silane gas outlet 122 having a cylindrical structure. Note that the hole diameter of the opening 132 provided in the electrode plate 131 is optimized depending on the size of the electrode plate 131 and the film thickness distribution of the silicon thin film deposited on the substrate 100, but more preferably 1-100 mm in diameter. A hole of several mm to several tens mm is desirable.

  The support member 151 is provided in a ring shape along the peripheral edge of the electrode plate 131, and the upper surface of the electrode plate 131 is fixed to the ground plate 110. An opening 111 is provided at a part of the position of the ground plate 110 to which the support member 151 is attached, and a support member 151 is formed on the inner surface of the opening 111 so as to cover the inner surface. An opening 152 that reaches the electrode plate 131 is also formed in the support member 151 in accordance with the position of the opening 111. Inside the opening 152 of the support member 151, a cable 141 extending from the high frequency power supply 14 is disposed so as to be connected to the electrode plate 131. The support member 151 is disposed at a distance from the side surface 123 of the silane gas storage supply chamber 120.

  As described above, the gap formed between the side surface 123 of the silane gas storage supply chamber 120 and the support member 151 and between the lower surface 124 of the silane gas storage supply chamber 120 and the electrode plate 131 is an upper ground plate 110. The hydrogen gas supply port 31 connected to the hydrogen gas supply line 32 is connected to form a hydrogen gas flow path 133. A gap (gap) formed between the outer wall of the silane gas outlet 122 and the side wall forming the opening 132 of the electrode plate 131 is connected to the hydrogen gas flow path 133 and is applied to the electrode plate 131. As a result, a hydrogen plasma generation unit 134 is generated in which hydrogen plasma is generated. The lower end of the hydrogen plasma generator 134 serves as a hydrogen plasma outlet 135 for blowing out hydrogen plasma toward the substrate stage 11.

  The gap in the hydrogen gas flow path 133 in the hydrogen gas supply unit 130 is selected such that the hydrogen gas is not discharged by the high-frequency power supplied to the electrode plate 131. Specifically, the gap in the hydrogen gas flow path 133 is changed from the minimum value of the Paschen curve representing the relationship between the discharge start voltage and the pressure in the discharge to a value at which the hydrogen gas does not discharge in the low pressure side and high pressure side regions. Set.

  On the other hand, a gap (a gap formed between the outer wall of the silane gas outlet 122 and the side wall forming the opening 132 of the electrode plate 131) in the hydrogen plasma generation unit 134 is generated by the high-frequency power supplied to the electrode plate 131. The interval at which the gas is discharged is selected. Specifically, it is set to a value at which hydrogen gas does not discharge in the minimum value region of the Paschen curve.

  Moreover, in the above description, as shown in FIGS. 2-1 and 2-2, the case where the plasma electrode 12 has a disk shape is given as an example. Or other shapes.

  Next, the operation at the time of producing a thin film in the thin film forming apparatus having such a configuration will be described with reference to FIGS. FIG. 3 is a cross-sectional view schematically showing a state when forming a thin film near the plasma electrode. First, the substrate 100 is transported into the film forming chamber 10, and the substrate 100 is held on the substrate stage 11, and then the film forming chamber 10 is brought to a predetermined vacuum level by a vacuum pump connected to the gas exhaust port 13. Next, the silane gas whose flow rate is controlled by the mass flow controller 23 is introduced from the silane gas supply port 21 to the plasma electrode 12 through the silane gas supply line 22 from the silane reservoir. Further, the hydrogen gas whose flow rate is controlled by the mass flow controller 33 is introduced from the hydrogen gas reservoir through the hydrogen gas supply line 32 to the plasma electrode 12 from the hydrogen gas supply port 31 provided separately from the silane gas supply port 21. To do.

  As shown in FIGS. 2-3 and 3, the silane gas is supplied from the silane gas supply port 21 to the silane gas storage part 121 of the silane gas storage supply chamber 120 and stored therein. Thereafter, the gas is introduced into a space in the film forming chamber 10 through a plurality of silane gas outlets 122 provided at the bottom of the silane gas storage supply chamber 120. At this time, since the silane gas is introduced into the space in the film forming chamber 10 from the plurality of silane gas outlets 122 through the silane gas storage supply chamber 120, the supply amount is made uniform.

  As shown in FIGS. 2-3 and 3, one hydrogen gas passes through the hydrogen gas flow path 133 formed on the outer periphery of the silane gas storage supply chamber 120 from the hydrogen gas supply port 31, and the silane gas storage supply chamber. 120 are supplied to a plurality of hydrogen plasma generation units 134 formed below 120, and are introduced into a space in the film forming chamber 10 from a hydrogen plasma outlet 135 located at the lower end of the hydrogen plasma generation unit 134. With this configuration, hydrogen gas is supplied from the entire periphery of the silane gas outlet 122, so that a uniform flow rate of hydrogen gas can be introduced into the plurality of hydrogen plasma generation units 134 applied to the electrode plate 131. .

In general, since silane gas is easily dissociated by electron collision in plasma, if the plasma electron density is too high, a large amount of SiH ₂ , SiH, Si is generated, and particles are generated in the gas phase, causing defects. Many silicon thin films are formed. Therefore, in order to form a high-quality silicon thin film, it is important to generate preferable SiH ₃ molecules more selectively. Therefore, it is effective to set the high frequency power low to keep the plasma density low.

On the other hand, hydrogen gas is known to be a gas species that is relatively difficult to dissociate. This is because H atoms generated by electron impact dissociation in plasma easily recombine in the gas phase or on the wall of the film forming chamber 10 (vacuum vessel) or the electrode surface and return to H ₂ molecules. is there. For this reason, in order to increase the density of H atoms in the plasma, it is effective to increase the electron density in the plasma.

Here, the plasma density of hydrogen plasma is increased to 1 × 10 ¹⁰ (cm ⁻³ ) or higher, and the plasma density of silane plasma is decreased to 1 × 10 ¹⁰ (cm ⁻³ ) or lower. The reason for the hydrogen plasma is that the higher the density, the more hydrogen atoms are generated, and the crystallization is promoted. In the parallel plate type plasma apparatus, since the plasma density generally generated is 1 × 10 ⁹ (cm ⁻³ ) to 1 × 10 ¹¹ (cm ⁻³ ), the above value is used. As for silane plasma, when the plasma density is high, dissociation of silane proceeds and atoms / molecules other than SiH ₃ bonds required for film formation are generated. Therefore, in the parallel plate type plasma apparatus, the low density region of plasma generally generated is set to 1 × 10 ¹⁰ (cm ⁻³ ) or less.

As is well known, a microcrystalline silicon thin film is formed by exposing an amorphous silicon thin film to hydrogen plasma to crystallize the film. Therefore, in order to deposit a high-quality microcrystalline silicon thin film at a high speed, a high-quality silicon thin film is deposited by decomposing silane gas at a low electron density so that SiH ₃ molecules are selectively generated. It is necessary to decompose the hydrogen gas with the electron density to generate H atoms necessary for microcrystallization of the silicon thin film.

  In order to satisfy such conflicting requirements, in this embodiment, as shown below, the generation of hydrogen plasma and silane gas plasma is performed separately. That is, as shown in FIG. 3, the hydrogen gas introduced into the hydrogen plasma generation unit 134 is discharged by the high frequency power supplied to the electrode plate 131, and the hydrogen plasma 201 is generated. In addition to the hollow cathode effect described in Patent Document 1, the hydrogen plasma 201 generated here is arranged coaxially with the side wall forming the opening 132 of the electrode plate 131, and is a silane gas outlet that is set to the ground potential. Due to the high-frequency current flowing in the outer wall 122, the hydrogen plasma 201 becomes a higher density. As a result, a large amount of H atoms are generated, so that the amorphous silicon thin film formed on the substrate 100 can be microcrystallized at high speed. Note that the high-density hydrogen plasma 201 generated by the hydrogen plasma generation unit 134 diffuses in the direction toward the substrate stage 11 and becomes downflow plasma 202 in which the plasma density gradually decreases.

On the other hand, the silane gas introduced from the silane gas outlet 122 of the silane gas storage supply chamber 120 into the film formation chamber 10 is discharged in the silane gas storage supply chamber 120 because the silane gas storage supply chamber 120 is at ground potential. Instead, in the region near the silane gas outlet 122, the hydrogen plasma downflow plasma 202 blown out from the hydrogen plasma outlet 135 becomes the silane plasma 203 (by being brought into contact with the downflow plasma 202). Since this region is a hydrogen downflow plasma 202 and is diffused, and the plasma density is low, SiH ₃ molecules preferable for forming a high-quality silicon thin film are more selectively generated in the silane plasma 203. .

Thus, a low density silane plasma 203 (SiH ₃ plasma) suitable for the deposition of a high quality silicon thin film with few defects and a hydrogen containing a large amount of high density H atoms necessary for crystallization of the deposited silicon. Since the plasma 201 can be generated, a high-quality microcrystalline silicon thin film can be deposited on the substrate 100 held on the substrate stage 11 at a high speed.

  Finally, the results of film formation evaluation of the microcrystalline silicon film formed by the thin film formation method described above will be described. Here, the silane gas flow rate is set to 100 sccm, the hydrogen gas flow rate is set to 900 sccm (silane gas flow rate ratio = 10%), the pressure in the film forming chamber 10 is set to 500 Pa, the high frequency power is set to 500 W, the plasma electrode 12 and the substrate 100 A silicon thin film is formed with a distance of 10 mm, a temperature of the substrate stage 11 of 200 ° C., and a film formation time of 10 minutes.

As a result of forming a silicon thin film under the above conditions, a deposition rate of 8.1 nm / s was obtained, and practical high-speed film formation became possible. Moreover, the crystallization rate in a silicon thin film was measured using Raman spectroscopy. Here, the crystallization rate of the silicon thin film is the ratio of the intensity I _c of the crystalline silicon peak at 520 cm ⁻¹ to the intensity I _a of the amorphous silicon peak at 480 cm ^{−1 in} the scattering spectrum of the produced silicon thin film obtained by Raman scattering. Can be obtained as As a result, the crystallization rate I _c / I _a of the silicon thin film manufactured under the above conditions was 7.2, which was within the range of values for a good microcrystalline silicon thin film. In this example, parameters such as gas flow rate, pressure, and electric power are fixed, but are not limited to these values.

According to this embodiment, the silane gas and the hydrogen gas are spatially separated and supplied to the film forming chamber 10, and the high-density hydrogen plasma 201 is generated in the vicinity of the hydrogen plasma outlet 135 so as to be on the substrate stage 11 side. The downflow plasma 202 whose plasma density is reduced by diffusion is generated as it moves toward the substrate stage 11, and the silane gas is blown out of the silane gas outlet 122 into the downflow plasma 202 of the hydrogen plasma to reduce the density. Silane plasma 203 (SiH ₃ plasma) was generated. As a result, SiH ₃ molecules are selectively generated in the silane plasma 203 having a low electron density. Therefore, while depositing a high-quality silicon thin film, hydrogen gas is decomposed at a high electron density to produce microcrystals of the silicon thin film. By generating H atoms necessary for the formation and exposure to an amorphous silicon thin film formed on the substrate 100, a microcrystalline silicon film can be formed at a higher deposition rate than conventional.

  As a result, the film formation time for depositing the microcrystalline silicon thin film on the photoelectric conversion device can be shortened as compared with the conventional case, and the throughput of the manufacturing process of the silicon thin film solar cell can be improved. There is an effect. In addition, since the deposition time of the microcrystalline silicon thin film can be shortened, energy consumption can be reduced. Furthermore, since a high-quality silicon thin film can be formed, the probability that a silicon thin film that does not meet the regulations as a product will be reduced, and raw materials can be used effectively.

  Furthermore, it is known that the photoelectric conversion device using an amorphous silicon thin film deteriorates in photoelectric conversion characteristics when used for a long time. There was a limit to the reliability and high performance used. Therefore, it has been desired to develop a photoelectric conversion device having a microcrystalline silicon thin film whose photoelectric conversion characteristics are not easily deteriorated even when used for a long time as compared with an amorphous silicon thin film. Since the microcrystalline silicon thin film can be formed at the same deposition rate as that for forming the amorphous silicon thin film, the photoelectric conversion device having the microcrystalline silicon thin film manufactured in this embodiment is amorphous. Compared to a photoelectric conversion device having a silicon thin film, it can be used for a long period of time and has the effect of improving durability.

  As described above, the thin film forming method according to the present invention is useful for manufacturing a solar cell having a microcrystalline silicon thin film in a photoelectric conversion layer.

It is a figure which shows an example of schematic structure of the thin film forming apparatus by this embodiment. It is a top view of a plasma electrode. It is a bottom view of a plasma electrode. It is AA sectional drawing of FIGS. It is sectional drawing which shows typically the mode at the time of thin film formation of plasma electrode vicinity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Deposition chamber 11 Substrate stage 12 Plasma electrode 13 Gas exhaust port 14 High frequency power supply 21 Silane gas supply port 22 Silane gas supply line 23 Mass flow controller 31 Hydrogen gas supply port 32 Hydrogen gas supply line 33 Mass flow controller 100 Substrate 110 Earth plate 120 Silane gas storage Supply chamber 121 Silane gas reservoir 122 Silane gas outlet 130 Hydrogen gas supply part 131 Electrode plate 133 Hydrogen gas flow path 134 Hydrogen plasma generation part 135 Hydrogen plasma outlet 141 Cable 151 Support member 201 Hydrogen plasma 202 Downflow plasma 203 Silane plasma

Claims (5)

A substrate stage and a plasma electrode are arranged opposite to each other in a film forming chamber, and a silane gas and a hydrogen gas are supplied to the plasma electrode and a high frequency voltage is applied to generate plasma, and the substrate is held on the substrate stage. In a thin film forming apparatus for forming a microcrystalline silicon thin film on top,
Silane gas supply means for blowing the silane gas supplied to the plasma electrode from the outside of the film forming chamber onto the substrate;
The hydrogen gas supplied to the plasma electrode from the outside of the film forming chamber is converted into hydrogen plasma, and blown onto the substrate so as to come into contact with the silane gas blown from the silane gas supply means, and the silane gas is turned into plasma. Hydrogen gas supply means to be converted,
Equipped with a,
The silane gas supply means has a ground potential and is provided with a silane gas storage chamber for storing the silane gas supplied from the outside and a plurality of the silane gas storage chambers on the substrate stage side, and a plurality of the silane gas supply means blows the silane gas to the substrate stage side. A cylindrical silane gas outlet,
The hydrogen gas supply means is composed of a conductive flat plate member having an opening corresponding to the formation position of the silane gas outlet, and is extrapolated to the silane gas outlet so as not to contact the silane gas supply means. An electrode plate to which a high-frequency voltage is applied, and a hydrogen gas flow path for carrying the hydrogen gas supplied from the outside through a side surface of the silane gas storage chamber to a space between the electrode plate and the silane gas storage chamber, the thin film forming apparatus according to claim Rukoto to have a. The hydrogen gas supply means generates hydrogen plasma containing hydrogen atoms and blows it out as a downflow plasma whose plasma density gradually decreases toward the substrate. The silane gas from the silane gas supply means is supplied to the downflow plasma. 2. The thin film forming apparatus according to claim 1, wherein a silane plasma containing SiH ₃ molecules is generated by contact. An interval between the electrode plate and the surface of the silane gas storage chamber on the substrate stage side is an interval at which no discharge occurs even when a high frequency voltage is applied to the electrode plate, and the silane gas blowout in the opening of the electrode plate the distance between the mouth, a thin film forming apparatus according to claim 1, wherein the discharge is an interval that occurs when applying a high frequency voltage to the electrode plate. In the thin film formation method in the film formation chamber in which the substrate stage and the plasma electrode are arranged to face each other ,
A first step of pre-Symbol composing the plasma electrode silane gas is supplied to the grounded plurality of cylindrical silane gas outlet, blown the silane gas directed onto the substrate held by the substrate stage,
A conductive flat plate member that constitutes the plasma electrode in the film forming chamber and has an opening corresponding to a position where the silane gas blowing port is formed, and is disposed so that the silane gas blowing port and the opening do not contact each other. the said opening, said separately supplying hydrogen gas and silane gas, a second step of the hydrogen gas from the opening Ru was blown toward on the substrate,
A high frequency voltage is applied to the flat plate member of the plasma electrode to generate hydrogen plasma from the hydrogen gas blown from the opening, and the hydrogen plasma is blown out from the periphery of the silane gas blowing port onto the substrate. A third step of allowing
A fourth step of converting the silane gas into plasma by the hydrogen plasma;
A thin film forming method comprising: In the third step, hydrogen plasma containing hydrogen atoms is generated to form downflow plasma in which the plasma density gradually decreases from the plasma electrode toward the substrate,
5. The thin film forming method according to claim 4 , wherein in the fourth step, silane plasma containing SiH ₃ molecules is generated from the silane gas by the downflow plasma.

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