JP3327391B2 - Thin film manufacturing apparatus and manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plasma CVD apparatus and a plasma CVD method for forming a thin film on a substrate using plasma energy, and more particularly, to a plasma CVD apparatus for forming a silicon-based thin film and a plasma CVD apparatus. The present invention relates to a plasma CVD method.

[0002]

2. Description of the Related Art The importance of devices such as thin film transistors and solar cells has been increasing because of the possibility of forming films at low temperatures, the ease of increasing the area, and the control of p and n. Conventionally, a method of forming a non-single-crystal silicon film by a plasma CVD method has been widely used. In this method, a silane gas is decomposed by high frequency discharge to deposit a non-single-crystal silicon film on a substrate. As the plasma CVD apparatus, there are an electrodeless discharge type and an ECR type, but a bipolar discharge type in which a plasma discharge is performed between a first electrode to which a high-frequency voltage is applied and a grounded second electrode. Are commonly used.

[0003]

However, this 2
In a polar discharge type plasma CVD apparatus, a high-quality non-single-crystal silicon film applicable to the above-described device,
For example, a substrate temperature of about 300 ° C. is required to obtain an amorphous silicon film. When a film is formed at a substrate temperature of about 200 ° C., the concentration of hydrogen in the film increases, and the silicon density becomes coarse, so that the film cannot be applied to the above-described device. As for the formation of an insulating film such as an amorphous silicon nitride film, the quality of the film is significantly degraded even at a low temperature. On the other hand, if a high-quality non-single-crystal silicon film can be formed at a low substrate temperature of about 200 ° C., thermal energy can be saved and a film can be formed on a substrate such as plastic. The device application range is widened.

Accordingly, an object of the present invention is to provide a plasma CVD apparatus and a film forming method capable of forming various high-quality non-single-crystal silicon films using a new plasma control method even at a lower substrate temperature than before. It is to provide a method.

[0005]

According to the present invention, there is provided a plasma CVD apparatus for forming a non-single-crystal silicon film or a non-single-crystal silicon compound using a silane-based gas. A vacuum vessel in which the discharge takes place,
A first raw material gas is supplied into the vacuum chamber in a shower shape, a high-frequency power is supplied to the first flat electrode serving as a first plasma source, and the first flat electrode is parallel to the first flat electrode in the vacuum chamber. And a second plate electrode having a mechanism for holding a substrate, and a second source gas is provided between the first and second plate electrodes and near the surface of the second plate electrode. possess a gas supply mechanism, wherein the first plate electrode
Between the gas supply mechanism and the gas supply mechanism
Plasma CVD apparatus, characterized by Rukoto plasma is generated between the second plate electrode and is provided.

Preferably, the gas supply mechanism includes a metal pipe having a gas introduction hole, and the metal pipe is supplied with high-frequency power to constitute a second plasma source, or In addition to the gas supply mechanism, an antenna mechanism serving as a second plasma source is provided near the gas introduction hole of the gas supply mechanism. Still more preferably, the first plate electrode includes a magnetic field forming mechanism for forming a cusp magnetic field near a surface of the plate electrode.

[0007]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a plasma CVD apparatus according to a first embodiment of the present invention. In the figure, 1 is a vacuum vessel for forming a plasma discharge,
Reference numeral 2 denotes a first electrode, and the first electrode 2 is connected to a first high frequency power supply 3 for supplying high frequency power and a first matching circuit 4 to constitute a first plasma source. In addition, a first gas supply system 10 is provided with a plurality of gas introduction holes for supplying the raw material gas 5 in a shower shape.

Reference numeral 6 denotes a second electrode, which has a mechanism for mounting the substrate 7 and a heater 8 for controlling the temperature of the substrate. The second electrode is connected to a second high-frequency power supply 12 and a second matching circuit 13 provided outside the vacuum vessel so that high-frequency power can be supplied to the second electrode. By supplying high-frequency power to the second electrode, the ion energy on the surface of the substrate 7 can be controlled, and appropriate energy can be applied to the film deposition surface. In this case, it is effective to apply the high-frequency power at the lowest frequency at which the substrate surface does not charge up and at the highest frequency at which ions can follow. Therefore, 100 kHz or more 13.
It is preferable to apply a high-frequency power of a frequency of 56 MHz or less, which enables high-quality non-single-crystal silicon films to be formed at a low temperature of 200 ° C. or less. However, it is not always necessary to supply high-frequency power to the second electrode,
When a second plasma source described later is provided, only the plasma energy to be supplied may be sufficient. Reference numeral 9 denotes a gas introduction pipe provided between the first electrode 2 and the second electrode 6, which comprises a plurality of gas introduction holes 9a and constitutes a second gas supply system 20. As can be seen from the drawing, only the second gas supply system 20 is depicted in a bird's-eye view. The gas introduction pipe 9 is formed of a hollow pipe, and is formed in a square annular structure having an outer peripheral size substantially equal to that of the second electrode. The gas introduction pipe 9 supplies the source gas 5 toward the second electrode 6 via the gas introduction hole 9a. The vacuum vessel 1 is provided with an exhaust device 11 that can control the pressure in the vacuum vessel.

A first electrode 2 serving as a first plasma source is supplied to a first high frequency power supply 3 at a frequency of 13.56 MHz to 500 MHz.
z is supplied from the first gas supply system 10 to form a silane plasma by supplying high-frequency power having a frequency equal to or lower than z, and silane plasma is formed from the second gas supply system 20. By introducing it near, a high-quality non-single-crystal silicon film can be formed. In addition, a silane gas, an ammonia gas,
Nitrogen gas or the like is introduced in the form of a shower, a plasma of the mixed gas is formed by the first plasma source, and hydrogen gas or a rare gas is introduced from the second gas supply system 20 to the vicinity of the substrate surface. A high-quality non-single-crystal silicon nitride film can be formed. Further, a silane gas, a phosphine gas, or the like is introduced in a shower form from the first gas supply system, and a plasma of a mixed gas of these gases is formed by the first plasma source. Can form a high-quality non-single-crystal n-type silicon film.

FIG. 2 is a view showing a plasma CVD apparatus according to a second embodiment of the present invention. In FIG.
The same reference numerals are given to the parts common to the parts in FIG. 1 according to the first embodiment, and the duplicate description will be appropriately omitted, but in this embodiment, the second gas The gas introduction pipe 9 constituting the supply system 20 is formed of a conductor, and is connected to a third high-frequency power source 14 outside the vacuum vessel.
And the third matching circuit 15 constitutes a second plasma source. That is, the gas introduction pipe 9 constituting the second gas supply system 20 also functions as an antenna, and functions like a coil of an inductively coupled plasma source.
In FIG. 2, for simplicity, the gas introduction pipe 9 is shown in a simplified form by a solid line. However, the gas introduction pipe 9 is actually constituted by a hollow pipe as shown in FIG. The gas introduction hole is opened so that the gas may blow out. FIG.
Hereinafter, for simplicity, the gas supply pipe 9 may be simplified and indicated by a solid line.

A silane gas is introduced in a shower form from a first gas supply system 10, and a silane plasma is formed by a first plasma source. 13.56 MHz from the third high-frequency power source 14 to the gas introduction pipe 9 as the second plasma source.
Supply high frequency power with a frequency of 500 MHz or less,
A hydrogen gas, a rare gas, or the like is introduced from the second gas supply system near the substrate surface, and plasma of these gases is selectively formed near the substrate surface. Further, by supplying high-frequency power to the second electrode and applying appropriate energy to the film growth surface, a high-quality non-single-crystal silicon film can be formed at a low temperature.

A silane gas, an ammonia gas, a nitrogen gas or the like is introduced from the first gas supply system 10 in the form of a shower, and a plasma of a mixed gas thereof is formed by the first plasma source. In addition, a hydrogen gas, a rare gas, or the like is introduced from the second gas supply system 20 to the vicinity of the substrate surface, and a plasma of these gases is selectively formed near the substrate surface by the second plasma source. By applying appropriate energy to the silicon nitride film, a high-quality non-single-crystal silicon nitride film can be formed at a low temperature. Ammonia gas and nitrogen gas may be supplied from the second gas supply system 20 side.
Further, a silane gas, a phosphine gas, or the like is introduced in a shower form from the first gas supply system, and a plasma of a mixed gas thereof is formed by the first plasma source. In addition, a hydrogen gas, a rare gas, or the like is introduced from the second gas supply system to the vicinity of the substrate surface, and a plasma of these gases is selectively formed by the second plasma source near the substrate surface. By applying appropriate energy, high quality non-single crystal n
The patterned silicon film can be formed at a low temperature. The phosphine gas may be supplied from the second gas supply system 20 side.

FIG. 3 is a view showing a plasma CVD apparatus according to a third embodiment of the present invention. The present embodiment is different from the second embodiment shown in FIG. 2 in that the gas introduction pipe 9 serving also as the coil of the second plasma source is spiral. As in the case of the second embodiment, the plasma formed by the second plasma source or the high-frequency power supplied to the second electrode is used to apply appropriate energy to the film growth surface, thereby achieving high quality. Various non-single-crystal silicon films can be formed at a low temperature.
In order to obtain a uniform and good film quality of the silicon film, it is preferable that the gas is uniformly supplied from the second gas supply system 20 onto the substrate. Therefore, in particular, the gas introduction hole 9
When a is opened downward, it is desirable to arrange the gas introduction holes as evenly as possible on the substrate. In the present embodiment, the gas supply tube can be more uniformly supplied on the substrate by adopting a folded spiral gas introduction tube in place of the rectangular annular gas introduction tube shown in FIGS. The plasma near the substrate surface formed by the second plasma source becomes more uniform. Therefore, a higher quality non-single-crystal silicon film can be obtained. The gas introduction pipe may have an appropriate shape other than the square annular or spiral shape described in the first to third embodiments. For example, the shape is a circular ring, a spiral shape, a zigzag shape, a comb shape, or the like. Further, the direction of the gas introduction hole is not limited to the downward direction, and an appropriate direction can be selected, such as, for example, turning obliquely downward and left and right.

FIG. 4 is a view showing a plasma CVD apparatus according to a fourth embodiment of the present invention. The present embodiment is different from the first embodiment shown in FIG. 1 in that a plurality of cusp field forming magnets 16 are provided inside the surface of the first electrode 2. The plurality of magnets are arranged such that adjacent magnetic poles are different from each other in a plane with respect to the surface of the first electrode 2, and a cusp magnetic field is uniformly formed below the first electrode. Due to the cusp magnetic field, the plasma is concentrated near the lower portion of the first electrode, and a high-density plasma of a raw material gas such as silane is formed. Further, since the substrate is away from the high-density plasma region, the film deposition surface is not damaged by high-energy charged particles in the plasma. Furthermore, by introducing a source gas such as hydrogen or a rare gas from the second gas supply system 20 toward the substrate surface, the film deposition surface can be appropriately activated. This makes it possible to form high-quality various non-single-crystal silicon films at a low temperature.

FIG. 5 is a view showing a plasma CVD apparatus according to a fifth embodiment of the present invention. The present embodiment differs from the second embodiment shown in FIG. 2 in that a plurality of cusp field forming magnets 16 are provided inside the surface of the first electrode 2. As in the case of the fourth embodiment, these plural magnets are arranged such that magnetic poles adjacent to each other are different in a plane, and a cusp magnetic field is formed uniformly below the first electrode. . With this cusp magnetic field,
The plasma concentrates near the lower part of the first electrode, and a high-density plasma of a source gas such as silane is formed, thereby greatly promoting the dissociation of the source gas. Further, since the substrate is away from the high-density plasma region, the film deposition surface is not damaged by high-energy charged particles in the plasma. Further, a source gas such as hydrogen, a rare gas, or the like is introduced from the second gas supply system toward the substrate surface, and at the same time, a hydrogen radical, a hydrogen ion, a rare gas, or a rare gas is selectively introduced near the substrate surface by the second plasma source. By generating gas radicals, rare gas ions, and the like, the film deposition surface can be more activated. Therefore, it becomes possible to form various high-quality non-single-crystal silicon films at a lower temperature.

FIG. 6 is a view showing a plasma CVD apparatus according to a sixth embodiment of the present invention. The third embodiment differs from the third embodiment shown in FIG. 3 in that a plurality of cusp field forming magnets 16 are provided inside the surface of the first electrode 2. According to the present embodiment, the same effect as that of the fifth embodiment can be obtained, and the plasma such as hydrogen gas formed near the substrate surface by the second plasma source becomes more uniform, and the film quality is improved. The uniformity within the substrate is further improved. In the fourth to sixth embodiments, a permanent magnet or an electromagnet can be used to form a cusp magnetic field. In particular, when an electromagnet is used, the direction in which current flows can be changed, or the current can be turned on / off intermittently.
By turning it off, there is an advantage that an arbitrary cusp magnetic field can be formed and the film forming speed and film quality can be freely controlled.

In these fourth to sixth embodiments,
The appropriate strength of the magnetic field is about several tens to several thousand gauss near the surface of the first electrode. The distance between adjacent magnets is preferably about 2 to 3 cm. In addition, it is not always necessary to arrange these magnets at equal intervals. For example, a configuration in which the intervals in the peripheral portion of the electrode are made dense to suppress a decrease in plasma density in the peripheral portion and to make the in-plane plasma density uniform. It may be. Due to the effect of such a magnetic field, high-density silane plasma is mainly formed near the surface of the first electrode, and the presence of silane radicals generated in the high-density plasma region and diffused therefrom is dominant on the substrate surface. Becomes

Further, since ions and radicals such as hydrogen and a rare gas are present at a high density on the substrate surface by the second gas supply system or the second plasma source, silane radicals important for film formation are removed. Energy is applied to the deposition surface from ions and radicals such as hydrogen and a rare gas, so that various high-quality non-single-crystal silicon films can be formed at a lower substrate temperature. In the fourth to sixth embodiments, the effect of the magnetic field enables high-speed film formation about 3 to 5 times faster than in the first to third embodiments.

FIG. 7 is a view showing a plasma CVD apparatus according to a seventh embodiment of the present invention. The present embodiment is different from the second embodiment shown in FIG. 2 in that an antenna 17 serving as a second plasma source is provided below the gas introduction tube 9 separately from the gas introduction tube 9. It is. The antenna 17 has a third high-frequency power supply 14 connected to a third matching circuit 15.
Connected through. Also in this embodiment,
The same effects as those of the second, third, fifth and sixth embodiments can be obtained.

FIG. 8 is a view showing a plasma CVD apparatus according to an eighth embodiment of the present invention. The present embodiment is different from the seventh embodiment shown in FIG. 7 in that a gas introduction pipe 9 is provided below an antenna 17 serving as a second plasma source. The point is that the hole 9a is opened inward so that the source gas 5 is introduced toward the center. With such a structure, the same effects as those of the second, third, fifth, sixth and seventh embodiments can be obtained. In the seventh and eighth embodiments, the antenna 17 does not need to be hollow, and the shape is not limited to a square, but may be any shape such as a circle, a polygon, or a spiral shape thereof.

FIG. 9 is a view showing a plasma CVD apparatus according to a ninth embodiment of the present invention. This embodiment differs from the seventh embodiment shown in FIG. 7 in that a cusp magnetic field forming magnet 16 is added inside the surface of the first electrode 2. Due to the cusp magnetic field, the plasma is concentrated near the lower part of the first electrode, and a high-density plasma of a source gas such as silane is formed, thereby greatly promoting the dissociation of the source gas. Further, since the substrate is away from the high-density plasma region, the film deposition surface is not damaged by high-energy charged particles in the plasma. Therefore, higher-speed low-temperature film formation can be performed as compared with the case of the seventh embodiment.

FIG. 10 is a view showing a plasma CVD apparatus according to a tenth embodiment of the present invention. The present embodiment is different from the eighth embodiment shown in FIG. 8 in that a cusp magnetic field forming magnet 16 is added inside the surface of the first electrode 2. Also in this embodiment, as described above, a higher-speed low-temperature film formation can be performed as compared with the eighth embodiment.

FIG. 11 is a voltage waveform diagram showing a first plasma generation method according to the present invention. The second, three, five,
In the CVD apparatus of the sixth, seventh, eighth, ninth and tenth embodiments, the first plasma source and the second plasma source can be driven independently. In the first plasma generation method, the second plasma source is operated continuously, and only the first plasma source is turned on and off intermittently at a period of 10 microseconds to 100 milliseconds. In this case, a source gas such as silane is introduced from the first gas supply system 10, and a hydrogen gas or a rare gas is introduced from the second gas supply system 20.

It is generally considered that SiH ₃ radical plays an important role in forming a high-quality non-single-crystal silicon film. As in this driving method, the relative density of SiH ₃ radicals in the silane plasma can be increased by periodically turning on and off the first plasma source and operating it intermittently. The reason is as follows. From the research results so far, it has been found that the lifetime of this SiH ₃ radical is longer than that of other radicals. Therefore, even when the output of the first high-frequency power supply is off, there are some SiH ₃ radicals in the container. On the other hand, other short-lived radicals almost disappear when the output is turned off. Therefore, considering the time average, the relative density of the SiH ₃ radical with respect to other radicals increases. Considering the lifetime of SiH ₃ radicals and other radicals, the ON / OFF cycle is suitably from 10 microseconds to 100 milliseconds. Furthermore, from the second gas supply system, a raw material gas such as hydrogen or a rare gas is introduced toward the substrate surface, and at the same time, by the second plasma source,
Selectively generate hydrogen radicals, hydrogen ions, rare gas radicals, rare gas ions, etc. near the substrate surface, activate the film deposition surface more, and form high-quality non-single-crystal silicon films at lower temperatures. It becomes possible. When a cusp magnetic field is used in combination, high-density plasma is generated, so that the SiH ₃ radical density also increases, and low-temperature and high-speed film formation becomes possible.

FIG. 12 is a voltage waveform diagram showing a second plasma generation method according to the present invention. In this driving method, not only the first plasma source but also the second plasma source is periodically turned on and off to operate intermittently. Specifically, the first plasma source and the second plasma source are turned on and off at a period of 10 microseconds or more and 100 milliseconds or less, and
The on / off phases are shifted from each other by 180 degrees. When the first plasma source is on and the second plasma source is off,
A silane plasma is formed in the container, and several layers are deposited on the substrate. In the next cycle, when the first plasma source is off and the second plasma source is on, hydrogen radicals, hydrogen ions, rare gas radicals, rare gas ions, etc. are mainly generated mainly near the substrate surface, The film deposited in the previous cycle is modified. By forming a film while repeating such film deposition and film modification, it becomes possible to form various high-quality non-single-crystal silicon films at a low temperature. At the same time, during the film reforming period, as described above, the long-life SiH
Because there are also _three radicals, a high quality film is also deposited. By forming a film while repeating such film deposition and film modification, it becomes possible to form various high-quality non-single-crystal silicon films at a low temperature.

Similar processing can also be performed by using the first high-frequency power supply and the second high-frequency power supply and turning them on and off with their phases shifted from each other. In the plasma CVD apparatus of each embodiment according to the present invention, the first electrode 2 serving as the first plasma source includes:
High frequency power of a frequency of 56 MHz to 500 MHz is supplied. 13.56 MH which is a normal commercial frequency
When a discharge is formed at a frequency in the VHF band higher than z, a high-density plasma is formed and the utilization efficiency of the source gas is improved,
High-speed deposition of high-quality films becomes possible. Further, when both the frequency of the VHF band and the cusp magnetic field are used, a further high-speed film formation is possible.

The plasma CV of each embodiment according to the present invention
In the D device, the second electrode 6 has a frequency of 100 kHz or more and 1
High frequency power of a frequency of 3.56 MHz or less is supplied. By applying high-frequency power of a relatively low frequency to the second electrode 6 in this manner, the ion energy on the substrate surface can be controlled. This is because an ion having a higher mass than an electron can follow an electric field change at a low frequency. By controlling such ion energy, appropriate energy can be applied to the film deposition surface, and a high-quality film can be formed at a low temperature. Further, by turning on / off the high frequency power supplied to the second electrode in synchronization with the on / off of the first plasma source and the second plasma source, hydrogen ions and rare gas ions on the film deposition surface can be obtained. Energy control can be varied, and it becomes easier to form a high-quality film at a low substrate temperature.

The plasma CV of each embodiment according to the present invention
The polysilicon film can be formed by using any of the D apparatuses and by using any of the above-described film forming methods.
In the film forming method according to the present invention, hydrogen radicals are particularly positively supplied to the substrate surface. Hydrogen radicals that have diffused to the film deposition surface deprive the surface of the hydrogen atoms and activate the surface. At this activation site, SiH ₃ radicals contribute to film deposition, and a high-quality polysilicon film having a very low hydrogen concentration in the film is formed. Further, by utilizing ion energy of a rare gas or the like, a high-quality polysilicon film having excellent crystallinity can be formed at a low temperature of about 300 ° C. With such high quality polysilicon film,
It has the same film quality as a film that has been subjected to conventional laser annealing.

[0029]

EXAMPLES Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to these examples. An embodiment of a CVD apparatus and a film forming method of the present invention based on the plasma CVD apparatus shown in FIG. 1 will be described. A high frequency power of 60 MHz was supplied to the first electrode 2, and a silane gas as a raw material gas was supplied into the discharge vessel 1 in a shower form from a plurality of gas introduction holes formed in the first electrode. The substrate 7 was placed on the second electrode 6, and the heater 8 was controlled so that the substrate temperature became 200 ° C.

The gas introduction pipe 9 serving as the second gas supply system is
A metal cylindrical pipe having an inner diameter of 3 mm and a wall thickness of 1 mm was formed into a rectangular shape having the same size as the second electrode. Gas introduction holes were formed at the bottom of the cylindrical pipe at intervals of about 1 cm so that gas was supplied toward the substrate surface. As the gas, hydrogen gas and xenon gas were supplied. As described above, the gas is supplied from the first gas supply system and the second gas supply system, and the pressure is adjusted using the exhaust device 11 so that the pressure in the discharge vessel becomes 5 Pa. A high frequency power of 60 MHz was supplied to the electrodes to form plasma. The non-single-crystal silicon film thus formed is subjected to FT-IR (Fourier transform-infrared).
When evaluated by the method, it was found that the hydrogen concentration in the film was 15% or less and a high-quality film having a higher Si—H bond density than the Si—H ₂ bond density was formed.
Further, plasma is formed by supplying a silane gas, an ammonia gas, and a nitrogen gas in a shower form from the first gas supply system into the discharge vessel, and supplying hydrogen gas and xenon gas from the second gas supply system. When the film was made, Si
A high-quality silicon nitride film having an NH bond density higher than the -H bond density could be formed. In addition, a silane gas and a phosphine gas are supplied from a first gas supply system into a discharge vessel in a shower state, and a hydrogen gas and a xenon gas are supplied from a second gas supply system to form plasma and form a film. As a result, a high-quality n-type non-single-crystal silicon film having a resistivity of 200 Ω · cm or less was formed.

An embodiment of the CVD apparatus and the film forming method of the present invention based on the plasma CVD apparatus shown in FIG. 2 will be described. A high frequency power of 60 MHz was supplied to the first electrode 2, and silane gas as a raw material gas was supplied in a shower shape from a number of gas introduction holes formed in the first electrode into the discharge vessel. The substrate 7 was placed on the second electrode 6, and the heater 8 was controlled so that the substrate temperature became 200 ° C. The distance between the first electrode and the second electrode is
It was set to 10-15 cm. The gas introduction pipe 9 has an inner diameter of 3 m
m, a metal cylindrical pipe having a thickness of 1 mm was formed into a rectangular shape having a size similar to that of the second electrode. In addition, it was installed at a position 4 cm above the second electrode. Gas introduction holes were formed at the bottom of the cylindrical pipe at intervals of about 1 cm so that gas was supplied toward the substrate surface.
As the gas, hydrogen gas and xenon gas were supplied. As described above, the gas is supplied from the first gas supply system and the second gas supply system, and the pressure in the discharge vessel is 5 Pa
The pressure was adjusted using the exhaust device 11 so that
12. A silane plasma is formed using a 60 MHz power supply as a first high frequency power supply, and 13.
Plasma of hydrogen gas or xenon gas was formed near the substrate surface using a power supply of 56 MHz. Since energy is applied to the substrate surface by the plasma of hydrogen gas or xenon gas as compared with the embodiment of the CVD apparatus of FIG. 1, a higher quality non-single-crystal silicon film can be formed.

Also, silane gas from the first gas supply system,
Ammonia gas and nitrogen gas were supplied into the discharge vessel in the form of a shower, and plasma was formed by supplying hydrogen gas and xenon gas from the second gas supply system. Thus, a high-quality silicon nitride film having a higher NH bond density was formed. In addition, a silane gas and a phosphine gas are supplied from a first gas supply system into a discharge vessel in a shower state, and a hydrogen gas and a xenon gas are supplied from a second gas supply system to form plasma and form a film. As a result, a high-quality n-type non-single-crystal silicon film having a resistivity of 150 Ω · cm or less was formed.

An embodiment of the CVD apparatus and the film forming method of the present invention based on the plasma CVD apparatus shown in FIG. 3 will be described. A high frequency power of 60 MHz was supplied to the first electrode 2, and a silane gas as a raw material gas was supplied into the discharge vessel in a shower form from a number of gas introduction holes formed in the first electrode.

The substrate 7 was placed on the second electrode 6, and the heater 8 was controlled so that the substrate temperature became 200 ° C. The gas introduction pipe 9 serving as the second gas supply system has an inner diameter of 3 m.
m, a metal cylindrical pipe having a wall thickness of 1 mm was formed into a rectangular spiral shape having the same size as the second electrode. Gas introduction holes were formed at the bottom of the cylindrical pipe at intervals of about 1 cm so that gas was supplied toward the substrate surface. Compared to the embodiment according to the CVD apparatus of FIGS.
The gas supply from the second gas supply system becomes more uniform near the substrate surface. As the gas, hydrogen gas and xenon gas were supplied.

As described above, the gas was supplied from the first gas supply system and the second gas supply system, and the pressure was adjusted using the exhaust device 11 so that the pressure in the discharge vessel was 5 Pa. . A silane plasma was formed using a 60 MHz power supply as a first high frequency power supply, and a hydrogen gas or xenon gas plasma was formed near the substrate surface using a 13.56 MHz power supply as a third high frequency power supply. Since energy is applied to the substrate surface by hydrogen gas or xenon gas plasma compared to the first embodiment,
Further, a high-quality non-single-crystal silicon film was formed. Also,
Plasma is formed by supplying silane gas, ammonia gas, and nitrogen gas from the first gas supply system into the discharge vessel in a shower form, and supplying hydrogen gas and xenon gas from the second gas supply system to form a plasma. As a result, a high-quality silicon nitride film having an NH bond density higher than the Si-H bond density was formed.

Also, silane gas from the first gas supply system,
When a phosphine gas is supplied in a shower shape into the discharge vessel, a plasma is formed by supplying hydrogen gas and xenon gas from the second gas supply system, and the film is formed, the resistivity is 150 Ω · cm or less. A high-quality n-type non-single-crystal silicon film could be formed.

An embodiment of a CVD apparatus and a film forming method of the present invention based on the plasma CVD apparatus shown in FIG. 7 will be described. In the CVD apparatus shown in FIG.
The distance between the antenna 17 and the antenna 17 was 4 cm, and the distance between the antenna 17 and the gas introduction pipe 9 was 2 cm. Except for this, a film was formed by the same method as in the example based on the CVD apparatus in FIG.

An embodiment of the CVD apparatus and the film forming method of the present invention based on the plasma CVD apparatus shown in FIG. 8 will be described. In the CVD apparatus shown in FIG.
The distance between the gas introduction pipe 9 and the gas introduction pipe 9 was 2 cm, and the distance between the gas introduction pipe 9 and the antenna 17 was 2 cm. And gas introduction pipe 9
The gas introduction hole 9a is provided on the side surface of the hollow pipe so that the gas is introduced toward the surface of the substrate. Except for this, a film was formed by the same method as in the example based on the CVD apparatus in FIG.

Although the preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these, and various modifications are possible within the scope described in the claims. It is. For example, a silicon oxide film, a silicon oxynitride film, p
The present invention can be applied to low-temperature film formation of a non-single-crystal silicon film or the like. Further, in the present invention, since hydrogen radicals are positively supplied to the film deposition surface, it is possible to form a high-quality polysilicon film having a hydrogen concentration of 5% or less at a low substrate temperature of about 300 ° C. This is because the film deposition proceeds while the hydrogen radicals take away the coating hydrogen from the film deposition surface, and a film having a high silicon atom density is formed. The polysilicon film thus formed has the same film quality as a film subjected to a conventional laser annealing process. Therefore, the conventional laser annealing is not required, and the cost of the process can be reduced. In addition, as a conventionally used means for achieving a uniform plasma density in a vacuum vessel, a structure in which a plurality of magnets are installed on the side surface of the vacuum vessel is used. It is also possible to make the plasma density more uniform by combining with the above structure.

[0040]

As is apparent from the above description, the plasma CVD apparatus of the present invention and the film forming method using the same at a low substrate temperature of 200.degree. A crystalline silicon film, a non-single-crystal silicon film doped with impurities, or a non-single-crystal silicon insulating film can be formed. Furthermore, since high-density plasma is generated and the decomposition efficiency of the source gas is improved,
As the efficiency of use of raw material gas improves and the amount of exhaust gas decreases,
An environment-friendly film forming process can be realized. Also, 30
If the substrate temperature is raised to about 0 ° C., it becomes possible to form a high-quality polysilicon film which does not require the conventional laser annealing. Further, since it is relatively easy to cope with an increase in the size of the vacuum container, it can be applied to a thin film transistor formation process for a liquid crystal display using a large glass substrate having a diagonal length of about 1 meter.

[Brief description of the drawings]

FIG. 1 shows a plasma C according to a first embodiment of the present invention.
It is a schematic diagram of a VD device.

FIG. 2 shows a plasma C according to a second embodiment of the present invention.
It is a schematic diagram of a VD device.

FIG. 3 shows a plasma C according to a third embodiment of the present invention.
It is a schematic diagram of a VD device.

FIG. 4 shows a plasma C according to a fourth embodiment of the present invention.
It is a schematic diagram of a VD device.

FIG. 5 shows a plasma C according to a fifth embodiment of the present invention.
It is a schematic diagram of a VD device.

FIG. 6 shows a plasma C according to a sixth embodiment of the present invention.
It is a schematic diagram of a VD device.

FIG. 7 shows a plasma C according to a seventh embodiment of the present invention.
It is a schematic diagram of a VD device.

FIG. 8 shows a plasma C according to an eighth embodiment of the present invention.
It is a schematic diagram of a VD device.

FIG. 9 shows a plasma C according to a ninth embodiment of the present invention.
It is a schematic diagram of a VD device.

FIG. 10 is a schematic view of a plasma CVD apparatus according to a tenth embodiment of the present invention.

FIG. 11 is an example of an output voltage waveform diagram of a high-frequency power supply supplied to the first and second plasma sources of the present invention.

FIG. 12 is another example of an output voltage waveform diagram of a high-frequency power supply supplied to the first and second plasma sources of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum container 2 1st electrode 3 1st high frequency power supply 4 1st matching circuit 5 Source gas 6 2nd electrode 7 Substrate 8 Heater 9 Gas introduction pipe 9a Gas introduction hole 10 First gas supply system 11 Exhaust device Reference Signs List 12 second high-frequency power supply 13 second matching circuit 14 third high-frequency power supply 15 third matching circuit 16 cusp magnetic field forming magnet 17 antenna 20 second gas supply system

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-6-260434 (JP, A) JP-A-11-168094 (JP, A) JP-A 8-37097 (JP, A) JP-A-5-37097 93277 (JP, A) JP-A-2-219218 (JP, A) JP-A-11-74201 (JP, A) JP-A-7-130719 (JP, A) JP-A-53-91665 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/205

Claims (17)

(57) [Claims] 1. A plasma C for forming a non-single-crystal silicon film or a non-single-crystal silicon compound using a silane-based gas.
A VD apparatus, comprising: a vacuum vessel in which discharge is performed; and a first plate electrode supplied with high-frequency power and serving as a first plasma source, supplying a first source gas into the vacuum vessel in a shower shape. A second flat plate electrode that is disposed in the vacuum vessel in parallel with the first flat plate electrode and has a mechanism for holding a substrate, and the second flat plate electrode is located between the first and second flat plate electrodes, have a, a gas supply mechanism for supplying a second material gas near the surface of the plate electrode, and the first plate electrode and the gas supply mechanism
Between, and the gas supply mechanism and the second plate electrode
Plasma CVD apparatus according to claim Rukoto plasma is generated between. 2. The plasma CVD apparatus according to claim 1, wherein the gas supply mechanism includes a pipe having a gas introduction hole. 3. The plasma CVD method according to claim 2, wherein the pipe is provided on the second flat plate electrode such that the gas introduction holes are evenly arranged on the substrate. apparatus. 4. The plasma CVD apparatus according to claim 2, wherein said pipe is processed into a circular or rectangular coil shape. 5. The method according to claim 2, wherein the pipe is a metal pipe, and the metal pipe is supplied with high-frequency power to constitute a second plasma source. Plasma CVD equipment. 6. The plasma CVD method according to claim 1, further comprising an antenna mechanism serving as a second plasma source near the gas introduction hole of the gas supply mechanism. apparatus. 7. The device according to claim 1, wherein the first plate electrode is provided with a magnetic field forming mechanism for forming a cusp magnetic field near a surface of the plate electrode. Plasma CVD equipment. 8. The plasma CVD apparatus according to claim 7, wherein the magnetic field forming mechanism comprises a plurality of permanent magnets or electromagnets having different magnetic poles adjacent to each other on the surface of the first plate electrode. . 9. The plasma CVD apparatus according to claim 1, wherein the second plate electrode is provided with a temperature adjusting unit or a temperature adjusting unit and a high-frequency power applying unit. . 10. A film forming method using a parallel plate type plasma CVD apparatus to which a first raw material gas is supplied in a shower form from a first flat plate electrode to which high-frequency power is supplied, wherein the second flat plate is used. While supplying the second source gas on the surface of the electrode by a gas supply mechanism different from that of the first flat plate electrode ,
Between the first plate electrode and the gas supply mechanism,
And, between the gas supply mechanism and the second plate electrode
A plasma CVD film forming method, wherein a film is formed while generating plasma . 11. A second plasma source for generating plasma near a gas introduction hole of the gas supply mechanism, wherein the gas supplied by the gas supply mechanism is ionized or radicalized by the second plasma source. The method according to claim 10, wherein the film is formed. 12. The plasma CVD film forming method according to claim 11, wherein the high-frequency power supplied to the first plate electrode is turned on and off at a period of 10 microseconds to 100 milliseconds. 13. The high-frequency power supplied to the second plasma source is turned on and off at the same period as the high-frequency electrode supplied to the first flat plate electrode and 180 degrees out of phase therewith.
13. The method according to claim 12, wherein the method is turned off. 14. The method according to claim 1, wherein the first plate electrode, or the first plate electrode and the second plasma source are provided with 13.5
The plasma CVD film forming method according to any one of claims 11 to 13, wherein high-frequency power having a frequency of 6 MHz to 500 MHz is supplied. 15. A high-frequency power having a frequency of 100 kHz or more and 13.56 MHz or less is supplied to the second plate electrode while heating the second plate electrode.
The plasma CVD film forming method according to any one of the above. 16. The high-frequency power supplied to the second plate electrode is turned on / off in the same cycle as the high-frequency power supplied to the first plate electrode and with a phase shift of 180 degrees from the high-frequency power. The plasma C according to claim 15, wherein
VD film forming method. 17. The method according to claim 17, wherein at least silane gas, or silane gas and phosphine gas, or silane gas and ammonia or nitrogen gas is supplied from the first plate electrode, and at least hydrogen gas or hydrogen gas and hydrogen gas is supplied from the gas supply mechanism. The rare gas is introduced to form a non-single-crystal silicon film or a non-single-crystal silicon film or a non-single-crystal silicon nitride film doped with phosphorus. Plasma CVD film forming method.