JP2008205280A - Film deposition device, method for forming thin film, and process for fabricating transistor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film deposition device and method in which the number of cleaning times can be decreased. <P>SOLUTION: The film deposition device 1 is arranged such that a shower plate 4 is connected with the same ground potential as a vacuum tank 2, an electrode plate 9 for arranging a substrate 10 is connected with an AC power supply 30, and an AC voltage of 100 kHz to 1 MHz is applied to the electrode plate 9. Since the applied voltage drops to kHz band from conventional MHz band, the distance between electrodes (the distance between the shower plate 4 and the electrode plate 9) can be increased. Since the frequency is low, even an ion having a heavier mass as compared with an electron can move while following up the frequency and the plasma sticks to the electrode plate 9 side. As a result, deposit adhering to the shower plate 4 decreases. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a plasma CVD technique for decomposing and forming a gas in a semiconductor film or an insulating film with plasma.

  A thin film transistor is one of the main functions in the configuration of a liquid crystal display. Its gate insulating layer (silicon nitride film), channel layer (amorphous silicon film), and ohmic contact layer (n-type amorphous silicon film) are formed by a plasma CVD method. A film is formed.

  Reference numeral 101 in FIG. 6 shows a conventional film forming apparatus (plasma CVD apparatus), and this film forming apparatus 101 has a vacuum chamber 109. A vacuum evacuation system 120 is connected to the vacuum chamber 109 so that the inside of the vacuum chamber 109 can be evacuated.

  The vacuum chamber 109 includes a container-like lower member 103 and a plate-like top plate member 102. The lower member 103 has a bottom face downward and an opening vertically upward. The top plate member 102 is placed on the edge of the opening of the lower member 103 via an insulating member 104. Therefore, the top plate member 102 and the lower member 103 are insulated.

A shower head 105 is provided on the surface of the top plate member 102 inside the vacuum chamber 109.
A shower plate 106 is attached to a surface of the shower head 105 facing the bottom surface of the vacuum chamber 109, and a substrate holder 107 is disposed at a position vertically below the shower plate 106.

  A raw material gas supply system 111 and a cleaning gas supply system 113 are connected to the shower head 105, and when a raw material gas or a cleaning gas is supplied to the shower head 105, a large number of discharge holes are formed in the shower plate 106. The supplied gas is configured to be introduced into the vacuum chamber 109.

  The substrate holder 107 is connected to the ground potential together with the lower member 103, and the shower plate 106 is connected to the high frequency power source 130 together with the top plate member 102, so that a high frequency voltage can be applied between the shower plate 106 and the substrate holder 107. Has been.

  When forming a thin film using the film forming apparatus 101, the vacuum chamber 109 is evacuated by the vacuum evacuation system 120 to form a vacuum atmosphere in the vacuum chamber 109, and then the vacuum chamber 109 is maintained while the vacuum atmosphere is maintained. The substrate 110 is carried in and placed on the substrate holder 107.

  After the temperature of the substrate 110 is raised to a predetermined temperature by the heater 108 in the substrate holder 107, the raw material gas is introduced into the vacuum chamber 109 from the shower plate 106, and between the shower plate 106 and the substrate holder 107 by the high frequency power supply 130. When a high frequency voltage is applied, glow discharge is generated by capacitive coupling using the shower plate 106 as a cathode electrode and the substrate holder 107 as an anode electrode, and plasma of a source gas is generated inside the vacuum chamber 109.

When the source gas activated by the plasma reaches the surface of the substrate 110, the reaction of the source gas proceeds on the surface of the substrate 110, and a reaction product is deposited. For example, when the source gas includes a silicon-containing gas and H ₂ gas, silicon containing a large amount of hydrogen is deposited as a reaction product, and an amorphous silicon film is formed on the surface of the substrate 110.

  If the silicon deposit adhered to the surface of the shower plate peels off and falls onto the surface of the substrate 110, defective products are generated. Therefore, after a predetermined number of substrates 110 are formed in the vacuum chamber 109, the cleaning gas is removed. When fluorine gas activated by plasma is introduced from the supply system 113 into the vacuum chamber 109 through the shower plate 106, silicon-based deposits attached to the inner wall surface of the vacuum chamber 109 are sublimated and removed.

  In a mass production apparatus of a liquid crystal display or the like, a cleaning process is typically performed every time several to ten or more substrates 110 are formed.

  In the conventional film forming apparatus (plasma CVD apparatus) 101 as described above, a high-frequency power source 130 with an oscillation frequency of 13.56 MHz is used, and in order to obtain a film forming speed capable of mass production at this frequency, It is necessary that the distance between the electrodes between the shower plate 106 and the substrate holder 107 is about 15 to 25 mm.

On the other hand, in order to generate plasma with a uniform density in the vacuum chamber 109, it is necessary to keep the electrodes parallel to each other. When the film formation apparatus 101 is used for a long time, a heated metal (many In the case of aluminum), there is a problem that the distance between the electrodes between the shower plate 106 and the substrate holder 107 becomes non-uniform.
When the distance between the electrodes is 15 mm, if the distortion of 1.5 mm occurs in the shower plate 106 or the substrate holder 107, an error of 10% is generated.

  By the way, in recent years, substrates used for the production of LCDs and solar cells are becoming larger, and accordingly, the shower plate 106 as a cathode electrode and the substrate holder 107 as an anode electrode are also enlarged. When the power supply voltage is a high frequency of 13.56 MHz, a standing wave is generated between the electrodes, the potential in the electrode surface becomes non-uniform, and it is theoretically difficult to activate the source gas uniformly. .

  Further, in the above-described conventional film forming apparatus 101, as shown in FIG. 3A, plasma is applied to a portion of the electrode space close to the anode electrode (substrate holder 107) and a portion close to the cathode electrode (shower plate 106). Since 125 is produced, the same degree of thin film is deposited on both electrodes.

For this reason, the deposition efficiency on the surface of the substrate 110 is about 50%, and a thin film deposited on the surface other than the surface of the substrate 110 is removed. Therefore, a long removal time by fluorine radicals is required, and the production efficiency is lowered.
Japanese Patent No. 3563092 JP-A-4-234121 Japanese Patent Laid-Open No. 5-16296

  The present invention provides a film forming apparatus and a film forming method capable of reducing the number of cleanings without depositing a thin film on a shower plate.

The present invention is a film forming apparatus, wherein a vacuum chamber, a shower plate disposed in the vacuum chamber, having a plurality of holes, and the shower plate are disposed on one side, and communicated with the inside of the vacuum chamber through the holes. A shower head having a cavity to be connected, a source gas supply system connected to the shower head and supplying a source gas to the cavity, and a substrate disposed in parallel to a position facing the shower plate in the vacuum chamber And an AC power source connected to the electrode plate and capable of applying an AC voltage of 100 kHz to 1 MHz to the electrode plate, wherein the vacuum chamber and the shower plate are connected to a ground potential. It is a membrane device.
The present invention is a film forming apparatus, wherein a heating device is disposed in the vacuum chamber, an insulator is disposed on the heating device, and the electrode plate is disposed on the insulator. And the electrode plate is a film forming apparatus insulated by the insulator.
The present invention uses a film forming apparatus having a vacuum chamber, a shower plate disposed in the vacuum chamber, and an electrode plate disposed in parallel with the shower plate, and a substrate is disposed on the electrode plate, A thin film forming method for introducing a raw material gas into the vacuum chamber from a plurality of holes provided in the shower plate and forming a plasma of the raw material gas to grow a thin film on the surface of the substrate. Is a thin film forming method in which the plasma is generated by applying an AC voltage of 100 kHz or more and 1 MHz or less to the electrode plate in a state where the pressure is 10 Pa or more and 500 Pa or less and the shower plate and the vacuum chamber are grounded.
The present invention is a thin film forming method, wherein the source gas includes a silane-based gas having silicon in a chemical structure, and an amorphous silicon thin film is grown on the substrate surface.
In the present invention, when one of the n-type and the p-type is the first conductivity type and the other is the second conductivity type, the first conductivity type channel layer and the channel layer are contacted to form a pn junction, respectively. Two ohmic layers of the second conductivity type, a gate insulating film disposed in contact with the channel layer, a gate electrode disposed in contact with the gate insulating film, and two ohmic layers, respectively An inversion layer having a conductivity type opposite to the channel layer is formed in a portion of the channel layer that contacts the gate insulating film by a gate voltage applied to the gate electrode, the source electrode and the drain electrode being connected. A transistor manufacturing method for manufacturing on a substrate a thin film transistor that connects two ohmic layers by the inversion layer and allows a current to flow between the source electrode and the drain electrode. Is placed on an electrode plate in a vacuum chamber, and a raw material gas of amorphous silicon is introduced into the vacuum chamber from a shower plate disposed opposite to the electrode plate, so that the pressure in the vacuum chamber is 10 Pa or more and 500 Pa or less. In the state where the shower plate and the vacuum chamber are grounded, an AC voltage of 100 kHz to 1 MHz is applied to the electrode plate to generate a plasma of the amorphous silicon source gas, and the channel layer and the ohmic layer A transistor manufacturing method for forming at least one of the above.
In the present invention, when one of the n-type and the p-type is the first conductivity type and the other is the second conductivity type, the first conductivity type channel layer and the channel layer are contacted to form a pn junction, respectively. Two ohmic layers of the second conductivity type, a gate insulating film disposed in contact with the channel layer, a gate electrode disposed in contact with the gate insulating film, and two ohmic layers, respectively An inversion layer having a conductivity type opposite to the channel layer is formed in a portion of the channel layer that contacts the gate insulating film by a gate voltage applied to the gate electrode, the source electrode and the drain electrode being connected. A transistor manufacturing method for manufacturing on a substrate a thin film transistor that connects two ohmic layers by the inversion layer and allows a current to flow between the source electrode and the drain electrode. Is placed on the electrode plate in the vacuum chamber, and a silicon nitride film source gas is introduced into the vacuum chamber from a shower plate disposed opposite to the electrode plate, and the pressure in the vacuum chamber is 10 Pa or more and 500 Pa or less. In the state where the shower plate and the vacuum chamber are grounded, an AC voltage of 100 kHz or more and 1 MHz or less is applied to the electrode plate to generate a source gas plasma of the silicon nitride film, thereby forming the gate insulating film This is a transistor manufacturing method.

  The present invention is configured as described above, and a raw material gas is introduced into a vacuum chamber, an alternating voltage is applied to an electrode plate on which a substrate is arranged to generate a glow discharge, and an activated raw material A thin film is formed on the substrate surface by gas.

  The source gas is a silane-based gas having silicon in the chemical structure, and a gas such as monosilane gas or disilane gas can be used. It is also possible to dilute the silane-based gas by containing H2, Ar, or He in the silane-based gas.

  In this case, an amorphous silicon thin film or a microcrystalline silicon thin film can be obtained. Although these silicon thin films exhibit intrinsic semiconductor characteristics, they can be made p-type by including a boron-based gas having boron in the chemical structure in the film forming gas. On the other hand, it can be made n-type by containing a phosphorus-based gas having phosphorus in the chemical structure. Boron-based gases include diborane. Phosphorus gases include phosphine.

With the film forming apparatus of the present invention, a silicon nitride film can be formed by adding a nitrogen-based gas having nitrogen in the chemical structure to a silane-based gas. In this case, monosilane can be used as the silane gas and ammonia gas can be used as the nitrogen gas.
Nitrogen gas can be used instead of ammonia gas, but ammonia gas is more reactive. Alternatively, both ammonia gas and nitrogen gas may be used.

  If the source gas introduced in this way is changed, a silicon nitride film that becomes a gate insulating film of a thin film transistor used in a liquid crystal display device or the like, a low impurity concentration amorphous silicon film that becomes a channel layer, and an n-type amorphous silicon that becomes an ohmic contact layer Can be formed.

These silicon nitride film, low impurity concentration amorphous silicon film, and n-type amorphous silicon may all be formed continuously, or a channel layer (low impurity concentration amorphous silicon film) may be formed according to the present invention. This thin film can be formed by a method different from that of the present invention.
Alternatively, only the gate insulating film and the channel layer may be formed by the method according to the present invention, and the other layers may be formed by different methods.

Reference numeral 51 in FIG. 4A denotes a glass substrate on which a gate electrode 53 is formed by sputtering.
On the glass substrate 51 and the gate electrode 53, as shown in FIG. 4B, a gate insulating film 54 made of a silicon nitride film, a channel layer 56 made of a low impurity concentration amorphous silicon film, and an n-type amorphous silicon film An ohmic layer 57 made of

  As shown in FIG. 5C, the channel layer 56 and the ohmic layer 57 are removed by etching while leaving the portions located on both sides of the gate electrode 53 and the portions on the gate electrode 53 connected to the portions located on both sides thereof. Then, as shown in FIG. 6D, a source electrode 58 and a drain electrode 59 connected to the ohmic layer 57 are formed on both sides of the gate electrode 53 by sputtering and etching, respectively. When the ohmic layer 57 on the gate electrode 53 is removed and the ohmic layer 57 connected to the source electrode 58 and the ohmic layer 57 connected to the drain electrode 59 are separated, as shown in FIG. can get.

  One of the separated ohmic layers 57 is a source layer, the other is a drain layer, has a conductivity type opposite to that of the channel layer, and is ohmically connected to the source electrode 58 and the drain electrode 59, respectively.

When a voltage is applied between the source electrode 58 and the drain electrode 59, a gate voltage is applied to the gate electrode, and an inversion layer having a conductivity type opposite to the channel layer is formed in a portion in contact with the gate insulating film of the channel layer The source layer and the drain layer are connected by the inversion layer, and a current flows between the source electrode and the drain electrode (conduction state).
When the application of the gate voltage is stopped, the inversion layer disappears and no current flows (blocking state).

FIG. 5F shows a state in which the protective layer 55 is formed.
The gate insulating film 54, the channel layer 56, and the ohmic layer 57 are formed at different frequencies, an aluminum electrode pattern is formed, and a source electrode 58, a gate electrode 53, and a drain electrode 59 are formed by wet etching. The mobility was measured. The measurement results are shown in the graph of FIG.

  When the frequency exceeds 1 MHz, the mobility decreases. When the frequency exceeded 1 MHz, the plasma of the present invention spread near the anode electrode and the cathode electrode, and a thin film was deposited on the shower plate surface. Therefore, it can be seen that the frequency needs to be 1 MHz or less. On the other hand, when the frequency was less than 100 kHz, it was difficult to match the power source and the discharge load, and discharge was not possible.

  Since the frequency drops from the conventional MHz band to the kHz band, the distance between the electrodes can be increased. Since the frequency is low, ions whose mass is heavier than electrons can move following the frequency, and the plasma sticks to the substrate electrode side. Since the deposit on the shower plate is reduced, the amount of delamination is also reduced, so that the number of cleanings can be reduced.

Reference numeral 1 in FIG. 1 represents a film forming apparatus as an example of the present invention.
The film forming apparatus 1 has a vacuum chamber 2. An evacuation system 20 is connected to the vacuum chamber 2 so that the inside of the vacuum chamber 2 can be in a vacuum atmosphere.

  A heating device 7 is disposed on the bottom wall inside the vacuum chamber 2. A plate-like insulator 8 is disposed on the heating device 7. An electrode plate 9 is disposed on the insulator 8, and the electrode plate 9 is insulated from the heating device 7 and the vacuum chamber 2 by the insulator.

A shower head 3 is disposed on the ceiling side inside the vacuum chamber 2.
A shower plate 4 is attached to the surface of the shower head 3 facing the bottom surface of the vacuum chamber 2, and the shower plate 4 is positioned vertically above the electrode plate 9.

A cavity is formed inside the shower head 3, and a number of holes communicating with the cavity are formed in the shower plate 4.
A raw material gas supply system 11 and a cleaning gas supply system 12 are connected to the shower head 3. When the raw material gas or the cleaning gas is supplied to the shower head 3, the supplied gas is supplied from the holes of the shower plate 4. It is configured to be introduced into the vacuum chamber 2.

The electrode plate 9 is connected to an AC power supply 30 and is configured to apply an AC voltage output from the AC power supply 30.
The electrode plate 9 and the shower plate 4 are arranged in parallel with a distance of 30 mm or more.

When forming a thin film using the film forming apparatus 1, the vacuum chamber 2 is evacuated by the vacuum evacuation system 20 and formed in a vacuum atmosphere in the vacuum chamber 2, and then the vacuum chamber 2 is maintained while maintaining the vacuum atmosphere. The substrate 10 is carried in and placed on the electrode plate 9.
When the heating device 7 is operated to generate heat, the substrate 10 disposed on the electrode plate 9 is heated via the insulator 8 and the electrode plate 9 by heat conduction.

  After the substrate 10 is heated to a predetermined temperature, a raw material gas is introduced from the shower plate 4 into the vacuum chamber 2, and an AC voltage having a frequency of 100 kHz to 1 MHz is applied to the electrode plate 9 by the AC power supply 30.

  The shower plate 4 is at a ground potential, glow discharge is generated by capacitive coupling using the shower plate 4 as an anode electrode (ground potential) and the electrode plate 9 as a cathode electrode, and plasma of the source gas is generated between the anode electrode and the cathode electrode. appear.

  Since the frequency of the applied voltage is low, the plasma 25 is located near the surface of the substrate 10 as shown in FIG. 3B, and when the activated source gas reaches the surface of the substrate 10, the substrate 10. The reaction of the raw material gas proceeds on the surface, and reaction products are deposited. Since the plasma 25 is far from the shower plate 4, a thin film is not deposited on the shower plate 4, but a large amount is deposited on the surface of the substrate 10, and the film forming speed is increased.

  For example, when the source gas includes a silicon-containing gas and a hydrogen gas, silicon containing a large amount of hydrogen is deposited as a reaction product, and an amorphous silicon film is formed on the surface of the substrate 10.

  If the silicon deposits adhering to the surface of the shower plate 4 peel off and fall onto the surface of the substrate 10, defective products are generated. Therefore, after a predetermined number of substrates 10 are formed in the vacuum chamber 2, cleaning is performed. When fluorine gas radicalized by plasma is supplied from the gas supply system 12 to the shower plate 4 and introduced into the vacuum chamber 2 from the shower plate 4, silicon-based deposits attached to the inner wall surface of the vacuum chamber 2 are sublimated and removed. Is done.

  In the conventional method, the applied voltage is a high frequency such as 13.56 MHz, the distance between the electrodes is as short as about 20 mm, and glow discharge is generated in almost the entire area between the electrodes except for the thin sheath in the vicinity of both electrodes. For this reason, radical species decomposed by glow discharge are deposited approximately 50% on the substrate surface and the counter electrode surface.

  When the applied voltage is 1 MHz or less as in the present invention, a phenomenon in which plasma discharge sticks in the vicinity of the applied electrode is observed. Therefore, when the substrate is placed on the electrode plate 9 and a voltage is applied to the electrode plate 9, the plasma 25, which is a gas decomposition source, can be generated only in the vicinity of the substrate 10, so that deposition can be performed on the surface of the substrate 10 very efficiently. it can.

  The reason why the plasma sticks in the vicinity of the applied electrode is that the frequency is lower than that of the conventional method, so that the distance between the electrodes is wider than that of the conventional method, and that heavy ions also vibrate following the frequency. .

  Since the deposition is actively performed on the surface of the substrate 10, adhesion to the shower plate 4 and the wall of the vacuum chamber 2 can be reduced. For this reason, the time and gas consumption of the internal cleaning using warming gas, such as NF3 conventionally performed by the device mass production apparatus, can be significantly reduced, which leads to environmental contribution and reduction of operation costs.

  Further, since the frequency is 1/10 or more lower than the conventional 13.56 MHz, there is no problem of plasma nonuniformity due to the in-plane voltage distribution due to the standing wave, and the distance between the electrodes can be increased. The tolerance for physical distortion and stagnation increases, and it is possible to easily cope with the manufacture of the most advanced 3m x 3m size devices.

  In addition, in order to obtain a TFT having good characteristics according to conventional common sense, it is necessary to form the interface between the gate insulating film and the channel layer with low damage. Therefore, a high frequency band is used so that the self-bias voltage is reduced. While attempts to reduce ion damage are common, the present invention uses the low frequency side of the kHz band in the opposite direction.

  The reason why a TFT with good characteristics can be obtained by the present invention is that the heavy ions follow the frequency, so that the interface tends to become electrically neutral, and the RF potential applied to the voltage rather than the self-bias is the ion acceleration. It is thought that this is an area that affects

  Although the vacuum chamber 2 is made of aluminum and the wall surface is connected to the ground potential, in order to prevent discharge between the electrode plate 9, the wall surface is made of an insulator 6 such as alumina or quartz as shown in FIG. It may be covered.

  The shower plate 4 may be heated to a predetermined temperature (for example, 80 ° C.) with warm water, or may be heated with a built-in heater. In particular, since the shower plate 4 is at ground potential, it is easier to provide a heater that energizes and generates heat as compared to a conventional shower plate to which a high-frequency voltage is applied.

The electrode plate 9 needs to be a metal, and aluminum or the like can be used. For the insulator 8, alumina or the like can be used, and it is desirable that the insulator 8 is formed in a plate shape and the electrode plate 9 and the heating device 7 are in close contact with each other in order to enhance heat conduction.
In the film forming apparatus 1 of the present invention, a microcrystalline silicon film can be formed when the flow rate ratio of H _{2 to} SiH ₄ is 10 times or more.

  When forming the channel layer of the TFT, the discharge can be turned on and off in a pulsed manner in order to reduce damage at the interface of the amorphous silicon thin film constituting the channel layer. The ON time and OFF time of the pulse are 5 μsec to 100 μsec, respectively. As a result, when the mobility of the TFT when it is not pulsed is 0.3, the mobility can be increased to about 0.5 when it is pulsed.

With the film forming apparatus 1, a silicon nitride film, amorphous silicon, and n-type amorphous silicon were continuously formed on the surface of the silicon wafer.
The source gas for the silicon nitride film was a mixed gas of monosilane, ammonia, and nitrogen gas, and a silicon nitride film with a film thickness of 250 nm was formed.

  Monosilane was used as the source gas for the amorphous silicon film, and the film thickness was 200 nm. For n-type amorphous silicon, monosilane and phosphine were used, and the film thickness was 50 nm. The distance between the electrodes between the shower plate 4 and the electrode plate 9 was 50 mm. The frequency was set to 800 kHz.

  For comparison, a film was formed by applying a high frequency voltage of 13.56 MHz to the shower plate 106 in the above-described conventional film forming apparatus 101. The results are shown in Table 1 (silicon nitride film) and Table 2 (amorphous silicon film) below.

  The dielectric strength and conductivity of the thin film formed by the conventional film forming apparatus and the thin film formed by the film forming apparatus of the present invention are comparable.

Sectional drawing explaining an example of the film-forming apparatus of this invention Sectional view of a film deposition system with an insulator attached to the vacuum chamber wall (A): The figure which shows typically the state which the plasma generate | occur | produced in the film-forming apparatus of a prior art, (b): The figure which shows the state which the plasma generated in the film-forming apparatus of this application typically (A)-(f): Sectional drawing explaining the manufacturing process of TFT Graph showing mobility measurement results Sectional drawing for demonstrating the film-forming apparatus of a prior art

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Film-forming apparatus 2 ... Vacuum chamber 3 ... Shower head 4 ... Shower plate 9 ... Electrode plate 10 ... Substrate 11 ... Raw material gas supply system 30 ... AC power supply

Claims (6)

A vacuum chamber;
A shower plate disposed in the vacuum chamber and having a plurality of holes;
The shower head is disposed on one surface, and has a cavity that communicates with the inside of the vacuum chamber through the holes;
A source gas supply system connected to the shower head and supplying source gas to the cavity;
An electrode plate that is provided in parallel to the position facing the shower plate in the vacuum chamber, and on which a substrate can be disposed,
An AC power source connected to the electrode plate and capable of applying an AC voltage of 100 kHz to 1 MHz to the electrode plate;
A film forming apparatus in which the vacuum chamber and the shower plate are connected to a ground potential. A heating device is disposed in the vacuum chamber, and an insulator is disposed on the heating device,
The electrode plate is disposed on the insulator;
The film forming apparatus according to claim 1, wherein the heating device and the electrode plate are insulated by the insulator. A vacuum chamber;
A shower plate disposed in the vacuum chamber;
Using a film forming apparatus having an electrode plate arranged in parallel with the shower plate,
A thin film in which a substrate is disposed on the electrode plate, a raw material gas is introduced into the vacuum chamber from a plurality of holes provided in the shower plate, plasma of the raw material gas is formed, and a thin film is grown on the surface of the substrate A forming method comprising:
The pressure in the vacuum chamber is 10 Pa or more and 500 Pa or less,
A thin film forming method for generating the plasma by applying an AC voltage of 100 kHz to 1 MHz to the electrode plate in a state where the shower plate and the vacuum chamber are grounded. The source gas includes a silane-based gas having silicon in a chemical structure,
A thin film forming method for growing a thin film of amorphous silicon on the surface of the substrate. When one of the n-type and p-type is the first conductivity type and the other is the second conductivity type,
A channel layer of a first conductivity type;
Two ohmic layers of a second conductivity type that are in contact with the channel layer and each form a pn junction;
A gate insulating film disposed in contact with the channel layer;
A gate electrode disposed in contact with the gate insulating film;
A source electrode and a drain electrode respectively connected to the two ohmic layers;
An inversion layer having a conductivity type opposite to the channel layer is formed in a portion of the channel layer in contact with the gate insulating film by a gate voltage applied to the gate electrode;
A transistor manufacturing method for manufacturing on a substrate a thin film transistor that connects two ohmic layers by the inversion layer and allows a current to flow between the source electrode and the drain electrode,
Placing the substrate on an electrode plate in a vacuum chamber;
From the shower plate disposed opposite to the electrode plate, the amorphous silicon source gas is introduced into the vacuum chamber,
The pressure in the vacuum chamber is 10 Pa or more and 500 Pa or less,
With the shower plate and the vacuum chamber grounded, an AC voltage of 100 kHz to 1 MHz is applied to the electrode plate to generate plasma of the amorphous silicon source gas, and the channel layer and the ohmic layer A transistor manufacturing method for forming at least one. When one of the n-type and p-type is the first conductivity type and the other is the second conductivity type,
A channel layer of a first conductivity type;
Two ohmic layers of a second conductivity type that are in contact with the channel layer and each form a pn junction;
A gate insulating film disposed in contact with the channel layer;
A gate electrode disposed in contact with the gate insulating film;
A source electrode and a drain electrode respectively connected to the two ohmic layers;
An inversion layer having a conductivity type opposite to the channel layer is formed in a portion of the channel layer in contact with the gate insulating film by a gate voltage applied to the gate electrode;
A transistor manufacturing method for manufacturing on a substrate a thin film transistor that connects two ohmic layers by the inversion layer and allows a current to flow between the source electrode and the drain electrode,
Placing the substrate on an electrode plate in a vacuum chamber;
From a shower plate disposed opposite to the electrode plate, a raw material gas of a silicon nitride film is introduced into the vacuum chamber,
The pressure in the vacuum chamber is 10 Pa or more and 500 Pa or less,
A transistor for forming the gate insulating film by applying an AC voltage of 100 kHz or more and 1 MHz or less to the electrode plate in a state where the shower plate and the vacuum chamber are grounded to generate a plasma of a source gas of the silicon nitride film Production method.

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