JPH07315826A - Polycrystalline silicon thin film and its production - Google Patents

Abstract

PURPOSE:To obtain a high-quality polycrystalline silicon thin film having excellent electrical characteristics in a low-temperature process, by making a film by sputtering under specific conditions in an environment in which a gas concentration of impurities is controlled during film forming. CONSTITUTION:Glow discharge for forming a film is generated by using a high frequency (preferably 60 to 300MHz) higher than 13.56MHz in an atmosphere having <=100ppb of gas concentration of impurities except hydrogen in a film-forming space during film formation and a polycrystalline silicon thin film is formed at a film forming speed of >=2nm/second. This polycrystalline silicon thin film has >=80% orientation of (110) plane formed on a substrate and a pillar-shaped structure. The unevenness of the surface of the polycrystalline silicon thin film is <=25nm P-V value and diameters of crystal particles are 0.01-1mum. Preferably the pressure of the film forming space is 1-15mTorr and the substrate temperature is 200-700 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polycrystalline silicon thin film and a method for manufacturing the same, and more particularly to a semiconductor for a thin film transistor which is preferably used in a liquid crystal display device or a semiconductor for a photosensitive drum of a copying machine, or The present invention relates to a polycrystalline silicon thin film that can be suitably used as a semiconductor for a photovoltaic element and a method for manufacturing the same.

[0002]

2. Description of the Related Art A polycrystalline silicon thin film refers to an aggregate of fine crystals. For example, it refers to an aggregate of silicon crystals having a length of several tens nm to several tens of μm. Such polycrystalline silicon can be obtained by many methods. Typical examples thereof include thermal CVD method and plasma CVD method.
Method, a method combining a plasma CVD method and an annealing method is known.

As the thermal CVD method, a thin film forming method is known in which a source gas such as a silane (SiH ₄ ) gas or a disilane (Si ₂ H ₆ ) gas is thermally decomposed. In this method, a glass substrate or a graphite substrate other than single crystal silicon is heated, and a raw material gas is supplied to the heated substrate to cause thermal decomposition of the raw material gas to form a polycrystalline silicon thin film on the substrate. However, the film forming temperature needs to be as high as 650 ° C. to 1000 ° C. because the raw material gas needs to be thermally decomposed, and an expensive substrate such as quartz glass having high heat resistance is required as a usable substrate.

Further, film formation at a high temperature may cause stress due to a difference in coefficient of thermal expansion between the substrate and the polycrystalline silicon thin film, which may cause warpage or peeling.

Further, the surface of the polycrystalline silicon thin film formed by the thermal CVD method often has irregularities of about several hundred nm. The manufacturing by the thermal CVD method has a simple structure of the manufacturing apparatus and is easy to control, but has some points to be improved in order to obtain the intended use and the desired characteristics.

As one of the methods for solving these problems, a method combining a plasma CVD method and an annealing method is known (NIKKEI MICRODEVIC).
ES June 1991 P40).

This method utilizes decomposition of a raw material gas such as SiH ₄ gas or Si ₂ H ₆ gas by glow discharge under reduced pressure, and contains hydrogen on a substrate heated to about 400 ° C. to 500 ° C. After the amorphous silicon is formed, it is annealed at about 600 ° C. in a hydrogen or nitrogen atmosphere to obtain polycrystalline silicon.

This method is widely used because a high quality polycrystalline silicon thin film can be obtained with good reproducibility and the substrate temperature can be lowered as compared with the thermal CVD method.

However, since this method requires complicated manufacturing steps and a high total cost, there is a demand for a method of manufacturing a high quality polycrystalline silicon thin film which does not require a substantial post-treatment step only in the film forming step.

In response to such a demand, SiH ₄ gas or Si ₂ H ₆ gas is further used as a raw material gas, and SiF ₄ gas or F ₂ gas is used as a raw material, and plasma decomposition / reaction of a mixed gas thereof is used. There is a technique using a plasma CVD method for forming a film (Japanese Patent Laid-Open No. 4-137724).

In other words, a gas containing silicon or fluorine is reacted and decomposed by plasma discharge of the above mixed gas to cause deposition of a silicon thin film on a substrate and etching of the silicon thin film with fluorine at the same time, and a high-quality polycrystalline silicon thin film is obtained. To form.

As another method for obtaining a polycrystalline silicon thin film, a high-purity argon gas is introduced into a deposition chamber evacuated to an ultrahigh vacuum, plasma discharge is performed with a high frequency power of about 100 MHz, and a silicon target is sputtered to 400 ° C. There is also a sputtering method for forming a polycrystalline silicon thin film on a substrate heated as described above (Presentation of Spring Lecture 1992 Spring Conference 1992, 39th Joint Lecture on Applied Physics).

[0013]

As described above, the polycrystalline silicon thin film formed by the thermal CVD method has a temperature of 650 ° C.
It is necessary to go through a high temperature process of up to 600 ° C. even at a temperature of up to 100 ° C. and a plasma CVD + annealing method. Therefore, it is necessary to use a very expensive material such as quartz or refractory metal for the substrate. In addition, since the thin film undergoes a high temperature process, the thin film is subjected to thermal stress and the substrate is warped, and impurities and the like from the substrate are diffused into the film to deteriorate electrical characteristics.

Further, in the plasma CVD + annealing method, it is necessary to perform at least two steps such as a film forming step + annealing step, so that the film forming cost is increased, and the film forming step is complicated, so that the yield is lowered. I also had problems.

In the plasma CVD method, it is possible to obtain a polycrystalline silicon thin film in one step. The film forming temperature is 3
Although it is an effective means because it has characteristics such as about 00 ° C., the film forming rate is very small at 0.03 nm / sec, and the industrial total cost becomes high, so that the demand for lower cost is not always satisfied. I can't say.

Further, the sputtering method requires the substrate temperature to be 400 ° C. or higher, and it cannot be said that the same problems as in the above-mentioned thermal CVD method can be sufficiently solved.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a high-quality polycrystalline silicon thin film having excellent electrical characteristics and the like in a lower temperature process, and a manufacturing method thereof. And

Another object of the present invention is to provide a method for producing a high-quality polycrystalline silicon thin film with good reproducibility and simpler steps.

In addition, an object of the present invention is to provide a polycrystalline silicon thin film which can be formed on a cheaper substrate and which can further reduce the total manufacturing cost.

Further, it is an object of the present invention to provide a polycrystalline silicon thin film having excellent semiconductor characteristics, which makes it possible to manufacture a high-performance semiconductor device without unnecessary diffusion of impurities in the substrate and other materials.

In the polycrystalline silicon thin film of the present invention which achieves the above object, the orientation of the (110) plane formed on the substrate is 8
It is characterized by having a columnar structure at 0% or more.

Further, the method for producing a polycrystalline silicon thin film according to the present invention, which achieves the above object, is performed in an atmosphere in which the impurity gas concentration other than hydrogen in the film forming space during film formation is 100 ppb or less.
A feature is that a glow discharge for film formation is generated by using a high frequency higher than 3.56 MHz, and polycrystalline silicon is formed by sputtering at a film formation rate of 2 nm / sec or more.

[0023]

The present invention has conducted research on the sputtering method which is the above-mentioned low temperature film forming process. As a result, Ar in the plasma is controlled under an environment in which at least the impurity gas concentration during the film formation is controlled.
By controlling the film formation rate by a sputtering method that narrows the energy distribution of ions, it is possible to obtain a polycrystalline silicon thin film with a grain size of about 60 nm on a glass substrate at a low temperature of about 300 ° C. It is based on the finding that it is possible to form high quality polycrystalline silicon.

The polycrystalline silicon thin film of the present invention is formed by sputtering on an arbitrary substrate and has a columnar structure with an orientation ratio of (110) plane of 80% or more, and more preferably a surface irregularity ( The PV value: the height from the concave portion to the convex portion is 25 nm or less. Further, it is more preferable that the crystal grain size is 0.01 μm to 1 μm. In this case, it is preferable that the grain size is the size of the crystal in the plane parallel to the substrate or the surface of the grain forming the columnar structure.

The polycrystalline silicon thin film of the present invention will be described in detail below.

In obtaining the polycrystalline silicon thin film of the present invention, an arbitrary substrate such as glass, ceramic or metal is used, and the polycrystalline silicon thin film is formed on this substrate by the sputtering method. When single crystal silicon is used as the substrate, either a polycrystalline silicon thin film or an epitaxial film can be obtained by selecting the conditions of the sputtering method.

In forming the polycrystalline silicon thin film of the present invention, 1. 1. Exclude impurities such as H ₂ O, CH _x , N _2, and CO _x from the film forming atmosphere, or exclude them as much as possible. 2. The energy distribution of positive ions incident on the target electrode and the film formation substrate during plasma discharge during sputtering is narrow. 3. The energy of positive ions incident on the film formation substrate is small. It is considered that the above four conditions are important, that the film formation rate is 2 nm / sec or more.

Argon gas is usually used as a gas used for forming polycrystalline silicon, but other than argon gas, helium gas, neon gas, krypton gas,
Xenon gas may be used. However, when helium gas and neon gas are used, the atomic mass is small, so the sputter rate may decrease and the film forming rate may decrease. When the krypton gas or the xenon gas is used, the sputter rate does not decrease, but the gas is expensive, which may increase the film forming cost.

Therefore, it is desirable that the gas to be used is appropriately selected in view of the total cost and availability.
Residual gas (H ₂ O ・ CH _X・ N ₂・ CO _X ) in the film forming chamber
Must be excluded as much as possible because it contaminates the film formation substrate surface during film formation with the impurity gas in the argon gas for discharge and inhibits the crystal growth of silicon. It is desirable that the partial pressure of each gas is set to 1 × 10 ^-10 torr or less, and similarly, the concentration of the impurity gas in the argon gas atmosphere for discharge is also set to 100 ppb or less.

Since the frequency of the electric power for converting the argon gas introduced into the film forming chamber into plasma is related to the energy distribution of the positive ions incident on the film formation substrate, 13.56M.
A frequency higher than Hz is good, and more preferably 60 MHz
~ 300 MHz. The power density and the DC potential not only affect the film formation rate but also the crystallinity of the polycrystalline silicon thin film, so the power density is preferably 0.1 W / cm ² to
10W / cm ^2, more preferably 5W / cm ² ~10W
/ Cm ^2, the target electrode is preferably -50V~-
The target is sputtered by applying a direct current potential of 800V, more preferably -100V to -500V, and the target is kept at a constant temperature of preferably 200 ° C to 700 ° C, more preferably 250 ° C to 600 ° C. Sputter film formation is performed on the film substrate. The substrate temperature is preferably as low as possible, but if it is lower than 250 ° C, the crystal grain size becomes too small and there is not much difference from that of amorphous.
If it is higher, the crystallinity is not improved so much and the advantage of low temperature film formation is lost.

Since the pressure during film formation is related to the energy amount of the positive ions incident on the substrate on which the film is to be formed, it is preferably 0.001 torr to 0.05 torr, and particularly 0.001 torr to. 0.015 torr
Is desirable.

Under the above conditions, not only an intrinsic polycrystalline silicon thin film can be formed, but also a target material doped with Group III and Group V dopants in the periodic table can be sputtered to obtain p-type and It is possible to obtain an n-type polycrystalline silicon film.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.
It goes without saying that appropriate modifications can be made as necessary.

Example 1 A method for producing a polycrystalline silicon thin film according to the present invention by a sputtering apparatus schematically shown in FIG. 1 will be described.

In FIG. 1, 1 is a target electrode for arranging the target 2, 4 is a film formation substrate holder for arranging the film formation substrate 3, 5 is a heater, 6 is a low-pass filter, and 7 is a DC power supply. , 8 is a high frequency power supply, 9 is a gas flow rate adjusting valve, 10 is an exhaust system conductance adjusting valve, 1
Reference numeral 1 is an exhaust system, 12 is a film forming chamber, and 13 is a gas cylinder (not shown).

In FIG. 1, a gas cylinder 13 (not shown) is filled with a gas for plasma discharge, and the gas for plasma discharge such as argon gas from this gas cylinder 13 is passed through a gas flow rate adjusting valve 9 to form a film forming chamber. 12 are supplied.

On the other hand, the film forming chamber 12 has an exhaust system 1 having a vacuum pump (not shown) (mechanical booster pump, rotary pump, oil diffusion pump, turbo molecular pump, etc.).
1 is connected via an exhaust system conductance adjusting valve 10.

The target electrode has a VHF wave band or RF
High-frequency power source 8 having a frequency in the wave band and VHF wave band or RF
Low-pass filter 6 for removing high frequency components in the wave band
The DC power supply 7 is connected via.

Hereinafter, this embodiment will be described more specifically.

After the film formation chamber 12 was evacuated to 1 × 10 ^-10 torr or less through an exhaust system connected to 11 in the figure, argon gas having an impurity concentration of 5 ppb was adjusted to 100 sccm by a flow rate control valve shown in 9 in the figure. The pressure in the film formation chamber was 4 mTorr. This argon gas is then
Power is supplied to the target electrode shown in 1 in the figure by using the high frequency power supply of 105 MHz shown in FIG. ³ to discharge at a power density of 6.4 W / cm ² , and further through the low pass filter shown in 6 in the figure. The target (p-type 0.01 Ωcm) shown in 2 in the figure is sputtered by applying -400 V to the target electrode from the negative electrode of the DC power supply shown in 7), and the film formation substrate holder (susceptor holder) 4 shown in the figure ) 4
A film was formed on the film formation substrate indicated by 3 in the figure placed above.

During film formation, the film formation substrate 3 was heated to 300 ° C. via the susceptor holder 4 by the heater shown in FIG.

The crystallinity of the obtained silicon thin film was examined by X-ray diffraction. A measurement chart is shown in FIG. AS
An X-ray diffraction chart of unaligned polycrystalline silicon based on the TM card (standard sample) is shown in FIG. The diffraction intensity ratio of unoriented polycrystalline silicon is shown in FIG.
As shown in (B), (111) :( 220) :( 31
1) :( 400) = 100: 55: 30: 5.

The X-ray diffraction intensity ratio of the polycrystalline silicon thin film obtained by the present invention is (111) :( 220) :( 3
11) :( 400) = 120: 20950: 145: 0
Then, when the orientation is calculated from the ratio of the standard value and the measured value,
(111): 0.3%, (220): 98%, (31
1): 1.3%, (400): 0%. (22
0) is equivalent to (110), and it can be seen that the orientation of the (110) plane is very strong in the polycrystalline silicon thin film of the present invention.

FIG. 3 shows a schematic sectional view from a TEM photograph of a section by a transmission electron microscope (TEM). As a result, the vicinity of the interface of the film-forming substrate is in an amorphous state, and crystallization starts halfway and almost completely crystallizes near the surface of the silicon thin film. Further, it can be seen that the surface property is very smooth with a P-V value of about 20 nm, although it is almost completely crystallized. The electrical resistivity of this thin film was measured and found to be 0.5 Ωcm.

Example 2 In order to evaluate the dependency of the film forming atmosphere on the impurity gas, the purity of Ar gas for plasma discharge was changed to change the amount of the impurity gas in the film forming atmosphere to deposit a silicon thin film. The film forming conditions other than the Ar gas purity are shown below.

Film forming pressure: 4 mtorr Film forming temperature: 300 ° C. High frequency power density: 6 W / cm ² High frequency power frequency: 105 MHz Target electrode potential: -400 V Target characteristic: P type, 0.01 Ωcm

The electrical resistivity of the obtained silicon thin film was measured and the results are shown in Table 1. From this result, it is expected that when the impurity concentration of the film forming atmosphere is 100 ppb or less, the electrical resistivity becomes stable, and the crystallinity of the polycrystalline silicon thin film becomes stable. In addition, in the evaluation by X-ray diffraction, no difference in crystallinity was found between the impurity concentrations of 25 ppb to 200 ppb.

[0048]

[Table 1]

Example 3 Ar for plasma discharge was used to evaluate the pressure dependence during film formation.
The pressure during film formation was changed by changing the gas flow rate to deposit a silicon thin film. The film forming conditions are shown below.

Film forming temperature: 300 ° C. High frequency power density: 6.4 W / cm ² High frequency power frequency: 105 MHz Target electrode potential: -400 V Target characteristic: p type, 0.01 Ωcm

The crystallinity of the obtained silicon thin film was evaluated by X-ray diffraction, and the electrical characteristics were evaluated by resistivity measurement. The X-ray diffraction chart is shown in FIG. 4A shows a film forming pressure of 4 mTorr, FIG. 4B shows a film forming pressure of 8 mTorr, and FIG. 4C shows a film forming pressure of 20 mTorr. When the film forming pressure is 4 mTorr, the (220) peak is the highest and the resistivity is also the lowest. 4mTorr for 8mTorr
The (220) peak becomes lower and the resistivity increases than in the case of. When the film forming pressure is 20 mTorr, the film is in an amorphous state. Table 2 shows the crystal orientation and electric resistivity depending on the film forming pressure.

From these results, it is expected that the film quality will be improved when the film forming pressure is low. However, when the pressure is lower than 1 mTorr, it becomes difficult to generate and maintain the plasma discharge, and further lowering the pressure becomes unrealistic.

[0053]

[Table 2]

Example 4 In order to evaluate the ion irradiation damage to the film formation surface during film formation, a negative potential was applied to the susceptor electrode to deposit a silicon thin film while irradiating the film formation surface with ions having different energies. did. Ion irradiation was performed by applying AC power of 140 MHz to the film formation substrate and applying a negative self-bias potential to the film formation substrate with respect to plasma. The film forming conditions are shown below.

Film forming pressure: 8 mTorr Film forming temperature: 500 ° C. High frequency power density: 3.8 W / cm ² High frequency power frequency: 105 MHz Target electrode potential: -400 V Target characteristic: P type, 0.01 Ωcm

The crystallinity of the obtained silicon thin film was evaluated by X-ray diffraction, and an X-ray diffraction chart is shown in FIG. Figure 5
(A) +1 with the film deposition substrate in a floating state
5V, FIG. 5B shows the film-forming substrate set to −24V, and FIG. 5C shows the film-forming substrate set to −60V. As shown in the figure, as the potential of the film formation substrate becomes negative, the peaks other than (220) increase and the crystal orientation disappears. Again 20
The broad peak of the amorphous layer near the temperature rises and the crystallinity deteriorates. From this result, it is understood that the smaller the energy of the ions irradiated on the film-forming surface, the better for the silicon thin film formation.

However, when a silicon thin film is deposited on an insulating substrate such as glass, it is physically impossible to apply a positive potential higher than the floating potential to the film forming substrate, so that the electron temperature of plasma is reduced, It is necessary to reduce the ion irradiation energy to the film formation substrate by reducing the difference between the plasma potential and the floating potential.

It was measured how the difference in the frequency of the electric power used for plasma generation affects the energy and irradiation amount of the ions irradiated on the film-forming surface, and the results are shown in FIG. From FIG. 6, it was found that when the frequency of the electric power used for plasma generation was increased, the energy of the ions irradiated on the film formation surface was decreased. However, when the frequency is 100 MHz or higher, the effect of increasing the frequency is reduced, and when the frequency is higher than a certain level, it becomes difficult to supply a large amount of power to the target electrode due to an increase in transmission loss in the device configuration of FIG. Therefore, it is practically desirable to generate plasma at 60 MHz to 300 MHz.

Example 5 A silicon thin film was deposited by changing the high-frequency power and the DC potential applied to the target electrode to change the film formation rate. Other film forming conditions are shown below.

Film forming pressure: 8 mTorr Film forming temperature: 300 ° C. High frequency power frequency: 105 MHz Target characteristic: P type, 0.01 Ωcm

Table 3 shows the film forming rate and the change in electric resistivity of the obtained silicon thin film. The upper part of the table shows the film formation rate (nm /
Second) and the lower part is the electrical resistivity (Ωcm). From this result, it can be seen that the higher the film formation rate, the smaller the electric resistivity and the better the film quality can be obtained. However, although it is recognized that the electrical resistivity has a dependency on the deposition rate, it does not show much correlation with the high frequency power and the DC potential of the target electrode.

Further, the change in crystallinity with respect to the change in film formation rate was evaluated by X-ray diffraction. The X-ray diffraction chart is shown in FIG. FIG. 7A shows a film forming rate of 1.5 nm / sec, and FIG.
Shows a film forming rate of 2 nm / sec, and FIG. 7C shows a film forming rate of 2.4 n.
It is a substance deposited at m / sec. From FIG. 7, the film formation rate is 2.4n
The material deposited at m / sec has the best crystallinity, and the film formation rate is 1.
It was found that the crystallinity of the polycrystalline silicon thin film improved as the film formation rate increased, because the crystallinity of the material deposited at 5 nm / sec was the worst.

Further, when the film forming rate is 2 nm / sec or more, the decrease rate of the electrical resistivity becomes small, so it is considered that the crystallinity and the electrical characteristics are stabilized in this range, and the film forming rate is 2 nm / sec.
It is necessary to form the film in more than a second to form a high quality polycrystalline silicon thin film.

Table 4 shows the relationship between the film formation rate and the surface roughness of the polycrystalline silicon thin film. From this result, it can be seen that the crystallinity of the silicon thin film is improved as the film formation rate is increased, and thus the surface of the silicon thin film becomes flat.

[0065]

[Table 3]

[0066]

[Table 4]

[0067]

As described above, according to the present invention, (11
0) A polycrystalline silicon thin film having a large orientation and good flatness can be obtained, which can be suitably applied to thin film transistors and the like, and can be applied to various fields such as large-screen liquid crystal televisions. Further, since it can be formed at a low temperature such as 300 ° C., it is possible to form a polycrystalline silicon thin film on various materials, for example, an inexpensive glass plate that could not be used conventionally can be used as a film formation substrate. Furthermore, since it can be created at a low temperature, it is possible to fabricate a higher performance semiconductor element in order to prevent substrate materials from diffusing into each other during film formation or in the case of a multi-layer film to prevent mutual diffusion of film materials. it can.

Further, the total manufacturing cost is low, and a polycrystalline silicon thin film having excellent characteristics and excellent yield can be formed.

[Brief description of drawings]

FIG. 1 is a sputtering film forming apparatus for obtaining a polycrystalline silicon thin film of the present invention.

2 is an X-ray diffraction chart of the polycrystalline silicon thin film of the present invention according to Example 1, FIG. 2A is an X-ray diffraction chart of the polycrystalline silicon thin film of the present invention according to Example 1, and FIG.
3 is an X-ray diffraction chart of polycrystalline silicon having no orientation based on a TM card (standard sample).

3 is a schematic sectional view from a TEM photograph of the polycrystalline silicon thin film of the present invention according to Example 1. FIG.

FIG. 4 is an X diagram showing pressure dependence during film formation in Example 3.
In the line diffraction chart, (A) is a film formed at 4 mTorr,
(B) is a film at 8 mTorr, (C) is 20 mTorr
This is the case when the film is formed by.

FIG. 5 is an X-ray diffraction chart showing ion irradiation dependence during film formation in Example 4, (A) shows a film formation substrate with a floating potential (+15 V), and (B) shows a film formation substrate. -2
FIG. 4C shows a case where -60V is applied to the film formation substrate.

FIG. 6 is a chart showing the discharge frequency dependence of the incident amount and incident energy of Ar ions with which the susceptor electrode is irradiated.

FIG. 7 is an X-ray diffraction chart showing film formation rate dependence in Example 5, (A) shows a film formation rate of 1.5 nm / sec.
(B) is a film forming rate of 2 nm / sec, (C) is a film forming rate of 2.4
This is the case of deposition at nm / sec.

[Explanation of symbols]

 1 Target Electrode 2 Target 3 Deposition Substrate 4 Deposition Substrate Holder 5 Deposition Substrate Heating Heater 6 VHF Removal Low Pass Filter 7 Target Electrode DC Power Supply 8 Plasma Generation High Frequency Power Supply 9 Plasma Discharge Gas Flow Control Valve 10 Exhaust system conductance adjustment valve 11 Vacuum exhaust system

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location C30B 29/06 504 B 8216-4G H01L 21/205 21/285 301 L 29/786 31/04

Claims (10)

[Claims] 1. A polycrystalline silicon thin film having a (110) plane orientation formed on a substrate of 80% or more and having a columnar structure. 2. The polycrystalline silicon thin film according to claim 1, wherein the surface roughness of the polycrystalline silicon thin film has a PV value of 25 nm or less. 3. The polycrystalline silicon thin film according to claim 1, wherein a crystal grain size of the polycrystalline silicon thin film is 0.01 μm to 1 μm. 4. 13.56 MH in an atmosphere in which an impurity gas concentration other than hydrogen in a film formation space during film formation is 100 ppb or less
A method for producing a polycrystalline silicon thin film, which comprises causing a glow discharge for film formation by using a high frequency higher than z, and forming the polycrystalline silicon thin film by sputtering at a film formation rate of 2 nm / sec or more. 5. The pressure in the film formation space during the film formation is 1 to 15
The method for producing a polycrystalline silicon thin film according to claim 4, wherein the polycrystalline silicon thin film is mTorr. 6. The method for producing a polycrystalline silicon thin film according to claim 4, wherein the high frequency higher than 13.56 MHz is 60 to 300 MHz. 7. The method for producing a polycrystalline silicon thin film according to claim 4, wherein a DC power source is connected to the target used for the sputtering. 8. The method for manufacturing a polycrystalline silicon thin film according to claim 7, wherein the negative electrode side of the DC power source is connected to the target. 9. The power density during the sputtering is 0.
1w / cm ² ~10w / cm ² a method for producing polycrystalline silicon thin film according to claims 4 to 8. 10. The substrate temperature during the film formation is 200 ° C. to 7 ° C.
It is 00 degreeC, The manufacturing method of the polycrystalline silicon thin film of Claim 4 thru | or 9.