JPH04355924A - Insulating film forming method - Google Patents

Abstract

PURPOSE:To obtain an insulating film having excellent interfacial characteristics by a method wherein a silicon oxide film is formed on a substrate by conducting a sputtering process in the prescribed oxygen atmosphere, and the silicon oxide film is annealed by hydrogen heat in the hydrogen atmosphere of the prescribed temperature. CONSTITUTION:A film is formed by sputtering in a 100% oxygen atmosphere using a metal oxide or a metal target, a hydrogen heat annealing operation is conducted in a hydrogen atmosphere at 250 to 350 deg.C, and an insulating film is formed. For example, on a polycrystalline silicon wafer 41, a silicon oxide film 42 is formed by a magnetron type RF sputtering device using a polycrystalline silicon target under the film forming condition of a 100% oxygen atmosphere, substrate temperature 150 deg.C, RF output 400W and film-forming pressure of 0.5 Pa. The formed silicon oxide film 42 is annealed by hydrogen heat for 30 minutes, and aluminum electrodes 43 and 44 are provided.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION The present invention provides a method for producing a silicon oxide film having excellent interfacial properties with a semiconductor interface.

0002

[Prior Art] In general, oxide insulating films are known as gate insulating films of insulated gate field effect transistors and base insulating films formed on glass substrates when semiconductor devices are formed on glass substrates. . Known methods for manufacturing the same include a thermal oxidation method, a photo-CVD method, and a sputtering method.

A typical example of the thermal oxidation method is to form a silicon oxide film on a substrate by reacting oxygen and silane at a temperature of 400 to 500°C or higher, but a thin film type insulated gate field effect method When attempting to form a gate insulating film of a transistor (hereinafter referred to as TFT) using this thermal oxidation method, the thermal energy at this time imparts one conductivity type to a semiconductor (for example, an N-type semiconductor or a P-type semiconductor). There is a problem in that impurities (for example, boron, phosphorus) diffuse into unnecessary parts of the genuine semiconductor or cause other unnecessary thermal damage.

[0004] However, the thermal oxidation method
Since a good interface state density of about cm-2 can be obtained, it is widely used despite the above-mentioned problems.

[0005] Furthermore, since the photo-CVD method is not affected by heat at all, it can solve the problems of the thermal oxidation method, and has the advantage of being able to realize interface states comparable to the thermal oxidation method. . However, it has the disadvantage that the film formation rate is very slow, resulting in low productivity. Furthermore, the ultraviolet light source typified by the UV light lamp used in the photo-CVD apparatus has a short lifespan and is expensive, which is a cost problem.

[0006] The sputtering method allows film formation at a low temperature of 150° C. or lower, has a fast film formation rate, and can uniformly form a film over a large area. Integrated circuits such as LSI, e.g. DRA
Films of tantalum oxide, titanium oxide, barium titanate, lead titanate, etc. used for capacitors in M (dynamic memory) cells can be formed by simply preparing a target. It has the following characteristics.

In particular, a silicon oxide film obtained by sputtering using a silicon target in a 100% oxygen atmosphere has a 7×10
It has a low interface state density of about 10 eV-1 cm-2, and since ions of argon atoms, which are unnecessary in silicon oxide films, do not exist in the film, it is stable with no fixed charges. It is possible to obtain a high-quality insulating film. However, the silicon oxide film obtained by sputtering in a 100% oxygen atmosphere would not be a practical insulating film unless it was hydrogenated by hydrogen thermal annealing.

[0008]

[Problems to be Solved by the Invention] A silicon oxide film obtained by sputtering cannot be put to practical use unless it is subjected to hydrogen thermal annealing. An object of the present invention is to obtain optimal conditions for this hydrogen thermal annealing.

[0009]

[Means for Solving the Problems] The present invention includes a step of forming an oxide insulating film on a substrate by sputtering in a 100% oxygen atmosphere, and a step of forming the oxide insulating film on a substrate in a hydrogen atmosphere at 250°C to 350°C. This is an insulating film manufacturing method characterized by hydrogen thermal annealing.

[0010] In the present invention, the substrate refers to a substrate such as a glass substrate, a semiconductor layer, or a metal, and the top surface, side surface, or periphery of the substrate is used for electrical insulation, electrical protection, or for the purpose of utilizing electronic phenomena in an insulating film. oxide insulating film is formed. An electronic phenomenon in an insulating film is, for example, an electronic phenomenon at the interface between an insulating film (insulator) and a semiconductor, and examples of its application include insulated gate field effect transistors (TFTs), MIM type elements, MIS type elements, etc. . Other methods using oxide insulating films include:
There are silicon oxide films formed as base films on glass substrates on which capacitors and semiconductor devices are formed in semiconductor integrated circuits.

[0011] The sputtering in the configuration of the present invention is as follows:
It is preferable to use a magnetron-type RF sputtering device, which is generally widely used when forming an insulating film.
Other sputtering methods may also be used. The reason why sputtering is performed in an atmosphere of 100% oxygen is to obtain a dense and electrically stable insulating film that does not contain impurities. In addition, thermal annealing at a temperature of 250 to 350°C in a 100% hydrogen atmosphere is 7 x 1010eV-1cm-2.
This is based on the experimental results conducted by the present inventor that it is optimal to perform thermal annealing for 30 to 60 minutes in this temperature range in order to obtain a good level of interface state. EXAMPLES The structure of the present invention will be explained in detail below with reference to Examples.

0012

【Example】

[Example 1] This example evaluates the characteristics of an insulating film in which a silicon oxide film is formed on a silicon substrate in a 100% oxygen atmosphere and then subjected to hydrogen thermal annealing at a temperature of 350 degrees for 30 minutes in a hydrogen atmosphere. This is what was done.

In this example, a silicon oxide film was formed on a silicon substrate as a sample using a maginetron type RF sputtering device. The preparation conditions for this sample were as follows: RF output: 4
00W, a film formation pressure of 0.5pa, an atmosphere of 100% oxygen, and a substrate temperature of 150°C. Furthermore, a polycrystalline silicon ingot was used as the target.

[0014] The substrate temperature during sputtering can be around room temperature. In addition, optical energy, electromagnetic energy,
Alternatively, using ECR conditions to make the oxygen atmosphere more active or more plasmatic (increase the degree of ionization) is effective for forming a dense oxide insulating film (silicon oxide film in this example). be.

FIGS. 1 to 3 are graphs showing the relationship between the oxygen partial pressure ratio in the film forming atmosphere and various characteristics of the silicon oxide film during sputtering of the silicon oxide film produced in this example. In this example, oxygen (O2) and argon (Ar
), and the oxygen partial pressure was changed by changing the mixing ratio of oxygen and argon. Oxygen partial pressure is defined as ((oxygen partial pressure/(oxygen partial pressure + argon partial pressure)). Therefore, an oxygen partial pressure ratio of 1.0 means an atmosphere of 100% oxygen. In this example, all parameters other than the oxygen partial pressure during film formation were performed under the same conditions.

FIG. 1 is a graph showing the relationship between the oxygen partial pressure ratio of the atmosphere during film formation and the interface state density at the interface between the silicon substrate and silicon oxide film of the sample. The interface state density was measured using the sample and measurement method described in Example 2.

FIG. 2 shows the relationship between the oxygen partial pressure ratio of the atmosphere and the flat band voltage VFB during film formation. In order to investigate the characteristics shown in Figure 2, a silicon oxide film (1000 Å thick) was used as a sample on a silicon semiconductor (200 μm thick).
was formed by a sputtering method, and this silicon oxide film was subjected to hydrogen thermal annealing at a temperature of 350° C. for 30 minutes in a hydrogen atmosphere, and an aluminum electrode of 1 mm diameter was formed on this silicon oxide film.

In this embodiment, hydrogen thermal annealing was performed using a diffusion furnace, but an LPCVD device, a thermal CVD device, or the like may also be used. Furthermore, in order to increase processing capacity, annealing is generally performed with the substrate in an upright position, but when a large-area glass substrate is used as the substrate, it is preferable to hold the glass substrate horizontally to even out the influence of gravity.

From FIG. 1, it can be seen that the higher the oxygen partial pressure during film formation, the lower the interface state density. In this case, since the conditions other than the oxygen partial pressure during film formation are the same, it can be considered that the interface state density depends on the oxygen partial pressure during film formation.

The flat band voltage VFB is a voltage necessary to cancel the influence of fixed charges in the insulating film, and the lower the value, the better the characteristics of the insulating film.

As is clear from FIG. 2, it can be seen that the flat band voltage decreases as the proportion of oxygen (oxygen partial pressure) in the atmosphere during sputtering increases. That is, FIG. 2 shows that the silicon oxide film obtained by sputtering in an atmosphere with a high oxygen content has excellent properties as an insulating film. Also, it is better to have the oxygen percentage as high as possible, preferably 100% oxygen.
It is also clear from FIGS. 1 and 2 that it is preferable to perform sputtering in an atmosphere of 50%.

FIG. 3 shows the relationship between oxygen partial pressure and dielectric breakdown voltage during film formation. The dielectric strength voltage in this case was defined as the voltage when the leakage current to the 1 mmφ aluminum electrode exceeded 1 μA. Since this measured value varies widely depending on the sample, X (center black dot) and σ (dispersion sigma value) (upper and lower limits) are shown. As is clear from Figure 3, the proportion of oxygen in the atmosphere during sputtering (
It can be seen that the larger the oxygen partial pressure), the higher the withstand pressure, and the smaller the variation depending on the sample. The large variation depending on the sample in the measurement of this breakdown voltage indicates that the stability as an insulating film is poor. Furthermore, it goes without saying that in mass production, it is undesirable from an industrial perspective for characteristics to vary.

It can be seen from FIG. 3 that the silicon oxide film formed by sputtering in a 100% oxygen atmosphere is the most electrically stable insulating film.

As shown in FIGS. 1, 2, and 3, when the proportion of argon in the atmosphere increases during film formation, the characteristics of the formed silicon oxide film as an insulating film deteriorate. The reason for this is that argon atoms, which are unnecessary impurities in the silicon oxide film, act as fixed charges in the silicon oxide film. Furthermore, damage to the surface of the silicon oxide film caused by argon ions during sputtering also causes variations in these characteristics.

In this example, silicon oxide is used as an example of the oxide insulating film. A metal oxide insulating film such as lead can be formed with the structure of the present invention. Specifically, a film is formed by sputtering using the metal oxide or metal target in a 100% oxygen atmosphere, and then hydrogen thermal annealing is performed in a hydrogen atmosphere at 250°C to 350°C to form an insulating film. It forms.

Furthermore, when the structure of the present invention is applied to forming a film of an oxide such as an oxide semiconductor, an oxide insulator, or an oxide superconductor by a sputtering method, it is possible to form a dense oxide. do not have. In this case, other suitable annealing methods may be used instead of hydrogen thermal annealing.

Above, in Example 1, the effect and basis of making the atmosphere 100% oxygen during film formation was explained through evaluation of the silicon oxide film formed by sputtering as an insulating film. 2, the effect and basis of hydrogen thermal annealing of the formed film in a hydrogen atmosphere at 250° C. to 350° C. will be explained.

[Example 2] In this example, hydrogen thermal annealing after sputtering, which is the structure of the present invention, will be explained based on experimental results. Figure 4 shows the well-known MIS as a sample of the insulating film evaluation method used for semiconductor devices.
The composition of the mold is shown. In the configuration shown in FIG. 4, a 200 μm thick polycrystalline silicon wafer 41 is placed on a 200 μm thick polycrystalline silicon wafer 41 in a 100% oxygen atmosphere, at a substrate temperature of 150° C.
Under the film forming conditions of RF output 400 W and film forming pressure 0.5 Pa,
Using a polycrystalline silicon target as a target, a silicon oxide film (SiO2) film 42 is formed using a magnetron type RF sputtering device, the formed silicon oxide film is subjected to hydrogen thermal annealing for 30 minutes, and aluminum electrodes 43 and 44 are further provided. It is something that The annealing time was 30 minutes, and hydrogen was flowed at 1 liter/minute at atmospheric pressure.

FIG. 5 shows the well-known Ramp Volta
It shows the CV characteristics at low frequencies obtained by adding ge. As a method for measuring C-V characteristics, aluminum electrode 4
This was done by applying a voltage to 3 and 44.

Each curve of the CV characteristic in FIG. 5 corresponds to a difference in temperature during hydrogen thermal annealing. As shown in FIG. 5, each curve showing the CV characteristics is given the temperature during hydrogen thermal annealing or its presence or absence. Parameters other than the hydrogen thermal annealing time are common to each sample exhibiting CV characteristics.

As shown in FIG. 5, the best C-V characteristics were obtained when the hydrogen thermal annealing temperature was 350 degrees. The evaluation method of this CV characteristic will be explained later as [supplementary explanation].

The steepness of the CV characteristic obtained by this measurement method is similar to that of ID -VG when the silicon oxide film used in this measurement is used as the gate oxide film of an insulated gate field effect transistor shown in FIG. It is directly reflected in the characteristics. Therefore, when the insulated gate field effect transistor shown in FIG. 6 is fabricated using a silicon oxide film with C-V characteristics at an annealing temperature of 450 degrees, which appears to have a good curve steepness, as the gate oxide film, the insulated gate field effect transistor shown in FIG. The partial disturbance of the curve shown in 4 directly appears in the ID-VG characteristics of the insulated gate field effect transistor, causing unstable operation.

Moreover, C- when the annealing temperature is 450 degrees
The interface state density at the interface between the insulating film and the semiconductor of the sample exhibiting V characteristics is higher than when the hydrogen thermal annealing temperature is 350 degrees. This is considered to be because a new level is generated in the forbidden band of the semiconductor in the vicinity of the interface, which causes some disturbance in the curve shown in FIG. 4 for some reason. One possible cause of this is the difference in thermal expansion coefficient between silicon and silicon oxide.

FIG. 6 shows an N-channel insulated gate field effect transistor (NTFT) as an example of an insulated gate field effect transistor (TFT). In FIG. 6, 61 is a glass substrate, 62 is a base silicon oxide film, 63 is a source region, 64 is a channel region, 65 is a drain region,
66 is a gate insulating film, 67 is a source electrode, 68 is a gate electrode, 69 is a drain electrode, and 601 is an interlayer insulator. Although NTFT is shown in FIG. 6, PTFT may also be used. Further, it goes without saying that the TFT is not limited to the format shown in FIG.

As can be seen from FIG. 5, the C-V characteristics of a silicon oxide film that is not annealed after film formation are nearly flat;
Even if this silicon oxide film is used as a gate oxide film, a good I
D -VG characteristic, that is, ID -VG with steepness
It is not possible to obtain an insulated gate field effect transistor with the characteristics.

FIG. 5 shows that the CV characteristics are improved by gradually increasing the temperature during annealing.

[0037] Also, the following

Table 1 summarizes the relationship between the interface state density at the interface between the silicon oxide film 42, which is an insulating film, and polycrystalline silicon 41 of each sample and the temperature during hydrogen thermal annealing.

[0038]

[Table 1]

As shown in Table 1, when the annealing temperature is 350
In the case of
It is about 2, but when the annealing temperature is 300 degrees, it is about 1.
x 1011 eV-1 cm-2, 3 x 1011 eV-1 cm-2 when the annealing temperature is 250 degrees, and 1 x 1012 eV-1 cm-2 when no annealing is performed.

The interface state can be measured using the well-known High Lo
w Frequency Measured using the CV method. This method is based on the C-V when a high frequency signal is applied.
From the comparison of the characteristics and the CV characteristics when a low frequency signal is added, the I and S of the MIS structure, that is, in this case, the insulating film 42
This is a method of determining the value of the interface state density at the interface between the polycrystalline semiconductor layer 41 and the polycrystalline semiconductor layer 41.

Comparing the interface state density of each sample shown in Table 1, the interface state density is the lowest when the hydrogen thermal annealing temperature is 350 degrees. A silicon oxide film at a temperature of 350 degrees is optimal.

The practical interface state density at the interface between the gate oxide film and the channel forming region of a typical TFT is 1.
If you want to find a value of about 011eV-1cm-2,
As in the configuration of the present invention, hydrogen thermal annealing is performed using hydrogen 100%
It can be concluded from Table 1 that annealing is preferably performed in an atmosphere of 250 to 350 degrees Celsius and annealing time of 30 to 60 minutes.

Regarding the annealing time, there was no significant difference in the effect even if the annealing was performed for 30 minutes or more. However, if the effect of hydrogen thermal annealing is to be obtained without variation, it is better to take 30 to 60 minutes.

In this example, if the atmosphere during annealing was a gas other than hydrogen, such as nitrogen, no effect could be obtained at all. The factors that cause the interface state density are:
Possible causes include bond defects caused by the structure and composition of the transition layer at the interface, that is, dangling bonds, point defects on the semiconductor surface, and disturbances in the bond length and bond angle of bonds near the interface. (Reference: Applied Physics Handbook P423 Published March 30, 1990 Published by Maruzen Co., Ltd.)

On the other hand, a method using hydrogen plasma is known as a method for neutralizing dangling bonds in an amorphous semiconductor. As mentioned above, if the generation of interface states is due to dangling bonds, point defects, or disordered bonds at the interface, it is natural that neutralization of dangling bonds by hydrogenation would have a large effect. It will be done.

In the structure of the present invention, hydrogen is used for annealing for the above reason, and it is clear that an inert gas is ineffective. However, for some reason, the hydrogen thermal annealing in the structure of the present invention may be performed in a mixed gas atmosphere of an inert gas and hydrogen.

In this example, oxygen 1
Sputtering is used in a 100% hydrogen atmosphere, and the formed silicon oxide film is completed by hydrogen thermal annealing in a 100% hydrogen atmosphere, and the hydrogen thermal annealing is an essential component.

Furthermore, the fact that the insulating film has good properties as a gate oxide film of an insulated gate field effect transistor guarantees that it has good properties as an insulating film used in all kinds of electronic devices. .

Generally, the basic requirements desired for an insulating film provided on a semiconductor surface are: (1) the interface state density is low and the fixed charge density at the interface can be controlled. (2) The film is dense and tightly adheres, providing sufficient protection to the semiconductor from the outside world. (3) Low stress at the interface. (4) It is thermally and chemically stable and has long-term reliability. (5) Good compatibility between the passivation film (insulating film) formation process and other device manufacturing processes. (6) Good step coverage. (Applied Physics Handbook P422 Published March 30, 1990 Published by Maruzen Co., Ltd.)

005
As explained in Example 2, the interface state density (1) can be achieved by changing the annealing temperature of thermal hydrogen annealing. In addition, fixed charges at the interface include sodium ions, alkali ions, etc., and a method for neutralizing these fixed charges is to use a target such as fluorine when sputtering in a 100% oxygen atmosphere. 0.1 to 5% by weight of halogen element or 1x phosphorus and boron
There is a method of mixing 1019 to 5 x 1020 cm-3. Further, these elements may be added to the atmosphere. In this way, it is also possible to control the fixed charge density at the interface in the configuration of the present invention.

Furthermore, (2) and (4) are one of the features of the present invention in that a dense oxide insulating film containing no impurities is obtained by sputtering in a 100% oxygen atmosphere. Regarding (3), considering the characteristics of the present invention that the film is formed by the sputtering method at a low temperature of 150 degrees or less, and the film is not contaminated with argon atoms as impurities, and there is no damage caused by the sputtering, the present invention It is clear that this is an effect that the configuration naturally has. (5) and (6) are of course the effects obtained by the configuration of the present invention, considering the characteristic of the well-known sputtering method that a film can be formed stably over a large area by the sputtering method.

[Supplementary Explanation] As a supplementary explanation, the relationship between the shape of the curve of the CV characteristic shown in FIG. 5 and the existence of interface states will be explained below. FIG. 7 shows an equivalent circuit of the sample having the MIS type configuration shown in FIG. 4, and the graph of FIG. 5 will be explained using FIG. 7, which is an equivalent circuit of FIG. 4, will be described below. In FIG. 4, a silicon oxide film and a polycrystalline silicon semiconductor film 41 sandwiched between aluminum electrodes 43 and 44 form a capacitor (capacitance C), but this capacitor C is composed of capacitors COX and CD of the silicon oxide film itself. is shown as a series combination of the capacitances of the depletion region of the semiconductor shown. Note that the capacitance CD of the semiconductor depletion region changes depending on the voltage applied to the electrode, so it is shown as a variable capacitor in FIG. Further, Ci is a capacitance caused by an interface state.

Hereinafter, the ideal interface characteristics in FIG. 4, that is, the CV characteristics in the case where the interface state is sufficiently small, that is, in the condition in which Ci can be ignored in FIG. 7, will be explained. In this case, a measurement signal voltage of a sufficiently low frequency is applied together with a DC bias so that the electrons can follow the signal voltage. (Reference: July 15, 1980, 3rd edition Published by Corona Publishing, Physics of Semiconductor Devices (2) P64)
Note that the voltage in this specification and in FIG. 5 indicates a DC bias voltage that is applied together with an AC signal.

If the interface characteristics between the polycrystalline silicon semiconductor 41 and the silicon oxide film 42 in the MIS structure shown in FIG. 4 are good, the interface state is considered to be negligible, so that Ci can be ignored. Therefore, capacitor C
is the following formula

[Math 1] is shown.

[0055]

[Math 1]

In addition, the standard value (C/
COX) is below

[Math 2] is shown.

[0057]

[Math 2]

Now, considering the case where a negative voltage is applied to the aluminum electrode 43 in FIG. 3, holes accumulate at the boundary between the polycrystalline silicon semiconductor film 41 and the silicon oxide film 42, so that
The capacitance CD of the polycrystalline silicon semiconductor film 41 increases. the result,

[Formula 2] As is clearer, C/COX approaches 1.

Furthermore, if the voltage applied to the aluminum electrode 43 is sufficiently small, the capacitance CD of the polycrystalline silicon semiconductor film 41 will be reduced by the depletion region formed near the interface between the polycrystalline silicon semiconductor film 41 and the silicon oxide film. The capacity decreases to only . As a result, the above formula

The value of C/COX shown in Equation 2 is smaller than 1.

Furthermore, when a positive voltage is applied to the aluminum electrode 43, electrons accumulate at the boundary between the polycrystalline silicon semiconductor film 41 and the silicon oxide film 42, so that the capacitance CD of the polycrystalline silicon semiconductor film 41 becomes negative. The voltage will increase in the same way as when the voltage is applied to the aluminum electrode 43. Therefore, C/COX approaches 1 in this case as well.

That is, in FIG. 4 (FIG. 7), the silicon oxide film 4
If the interface characteristics between 2 and the silicon semiconductor 41 are good,
When the voltage applied to the aluminum electrode 43 is changed from negative to positive, the value of C/COX changes from a value close to 1 to a value smaller than 1, and further becomes a value closer to 1.

The above case is an ideal model that ignores the interface states, but in this example shown in FIG. , it can be seen that this ideal CV characteristic is well matched.

Next, regarding the CV characteristics when interface states exist at a high density between the silicon oxide film and the polycrystalline silicon film in the configuration shown in FIG. 4, the equivalent circuit diagram of FIG. This will be explained using 7.

If an interface level, that is, a trap exists at the interface between a silicon semiconductor and a silicon oxide film which is an insulating film, Ci in FIG. 7 exists as a capacitor in terms of an equivalent circuit. Then, since there is a charge stored in the interface level, that is, the trap, Ci increases. Even if the voltage applied to the aluminum electrode 43 in Fig. 4 becomes zero and the CD becomes smaller, the following

[Math 3] (C/COX) shown as

The value of C/COX does not decrease as much as (C/COX) shown by (2), and as a result, the value of C/COX does not decrease by more than 1.

[0065]

[Math 3]

The behavior of the CV characteristics of a sample using an insulating film with such a high interface state density can be qualitatively explained by the above model. Therefore, in the C-V characteristic when the silicon oxide film without thermal annealing shown in FIG. 4 is used in the configuration shown in FIG. 3, the voltage applied to the electrode 43 is 0.
The value of C/COX does not become small even if

[0067]

Effects of the Invention The method of the present invention, in which a silicon oxide film obtained by sputtering in a 100% oxygen atmosphere is thermally annealed with hydrogen at a temperature of 250 to 350 degrees in a 100% hydrogen atmosphere, provides a good interface. It was confirmed that this is an insulating film manufacturing method that can obtain an insulating film with specific characteristics.

[Brief explanation of the drawing]

FIG. 1 shows the relationship between the interface state density and the oxygen partial pressure at the time of film formation of the sample prepared in this example.

FIG. 2 shows the relationship between the flat band voltage of the sample prepared in this example and the oxygen partial pressure during film formation.

FIG. 3 shows the relationship between the breakdown voltage of the sample prepared in this example and the oxygen partial pressure during film formation.

FIG. 4 shows the structure of the sample produced in this example.

FIG. 5 shows the CV characteristics of the sample produced in this example.

FIG. 6 shows an equivalent circuit of the sample produced in this example.

FIG. 7 shows a TFT as an example of a semiconductor device to which the configuration of the present invention can be applied.

[Explanation of symbols]

43, 44 Aluminum electrode 42 Silicon oxide film 41 Polycrystalline silicon 61
Glass substrate 62 Silicon oxide film 63 Source region 64 Channel formation region 65
drain region 66
Silicon oxide film 67 Source electrode 68 Gate electrode 69 Drain electrode 601
interlayer insulation film

Claims (1)

[Claims] 1. A step of forming a silicon oxide film on a substrate by sputtering in a 100% oxygen atmosphere, and thermally annealing the silicon oxide film in a hydrogen atmosphere at 250° C. to 350° C. Insulating film manufacturing method.