JPH1012609A - Semiconductor device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the electrical reliability of an insulating oxide film, such as the gate oxide film, etc., so as to improve the reliability of the element of a semiconductor device and reduce the manufacturing cost of the device by forming an oxide film containing heavy hydrogen atoms on the entire surface of a semiconductor substrate or semiconductor layer in both directions parallel to and perpendicular to the surface of the substrate. SOLUTION: An oxide film 13 containing heavy hydrogen atoms is formed on the entire surface of a semiconductor substrate 11 or semiconductor layer in both directions parallel to and perpendicular to the surface of the substrate. For example, after an element separating insulating film 12 is formed on the substrate 11, a gate oxide film 13 is formed by performing thermal oxidation using D2 O gas as a gaseous starting material. Then a polysilicon film 14 is deposited and, after the film 14 is selectively etched together with the oxide film 13 in a gate electrode pattern and side-wall insulating films 15 are successively formed, source and drain areas 16a and 16b are formed by implanting impurity ions into the substrate 11. Thereafter, a gate electrode 21, source electrode 22, and drain electrode 23 are formed after an interlayer insulting film 17 is deposited and a contact hole is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a technique for manufacturing the same, and more particularly to a semiconductor device in which an insulating oxide film such as a gate oxide film is improved and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a device in which a gate oxide film is used as a tunnel oxide film, such as a non-volatile semiconductor memory (EEPROM) capable of electrically writing and erasing, 10 MV is used for writing and erasing. / Cm is applied to the gate oxide. By applying a high electric field as described above to the gate oxide film,
Because electrons that have gained high energy from the electric field pass through,
High dielectric breakdown resistance is required for the gate oxide film.

In the conventional gate oxide film, various oxide films are formed by changing parameters such as a forming temperature and a forming atmosphere, and their electrical characteristics are evaluated to use a condition satisfying specifications. Techniques have been adopted. However, it is becoming difficult to satisfy the above-mentioned specifications under the current situation where the gate oxide film becomes increasingly thin. Furthermore, under the current situation where the types of products are diverse and the generations are changing rapidly, it is extremely inefficient to determine the conditions by the empirical method as described above, and it is important to increase the product cost. Disadvantages.

[0004]

As described above, the conventional EE
Although a gate oxide film used as a tunnel oxide film of a PROM is required to have high dielectric breakdown resistance, it is extremely difficult to satisfy such specifications, and this causes factors such as a reduction in device reliability and an increase in manufacturing cost. Had become.

The present invention has been made in consideration of the above circumstances, and has as its object to improve the electrical reliability of an insulating oxide film such as a gate oxide film and improve the reliability of an element. Another object of the present invention is to provide a semiconductor device and a method for manufacturing the same, which can reduce the manufacturing cost.

[0006]

[Means for Solving the Problems]

(Structure) In order to solve the above problem, the present invention employs the following structure.

(1) In a semiconductor device in which an oxide film is formed on the surface of a semiconductor substrate or a surface of a semiconductor layer, the oxide film has deuterium (D) in the entire region in the thickness direction and the surface direction.
It is characterized by containing atoms.

(2) In a method of manufacturing a semiconductor device including a step of forming an oxide film on a surface of a semiconductor substrate or a surface of a semiconductor layer, when the oxide film is formed, heavy water (D 2 O)
Is characterized by performing thermal oxidation using a gas containing

(3) In a method of manufacturing a semiconductor device including a step of forming an oxide film on a surface of a semiconductor substrate or a surface of a semiconductor layer, thermal oxidation is performed in active D atoms (D *) when forming the oxide film. It is characterized by doing.

(4) In a method of manufacturing a semiconductor device in which an oxide film is formed on the surface of a semiconductor substrate or a surface of a semiconductor layer, a step of forming an oxide film on the surface of the semiconductor substrate or the surface of the semiconductor layer, and then D Introducing D into the oxide film by ion implantation of ions.

(5) In a method of manufacturing a semiconductor device in which an oxide film is formed on the surface of a semiconductor substrate or a surface of a semiconductor layer, a step of forming an oxide film on the surface of the semiconductor substrate or the surface of the semiconductor layer, Exposing the oxide film to appropriate D atoms (D *) to introduce D into the oxide film.

(6) In a method of manufacturing a semiconductor device in which an oxide film is formed on the surface of a semiconductor substrate or a surface of a semiconductor layer, a step of forming an oxide film on the surface of the semiconductor substrate or the surface of the semiconductor layer, and then D Exposing it to a gas containing a compound of atoms and nitrogen atoms to introduce D into the oxide film.

(7) In a method of manufacturing a semiconductor device in which an oxide film is formed on the surface of a semiconductor substrate or a surface of a semiconductor layer, a step of forming an oxide film on the surface of the semiconductor substrate or the surface of the semiconductor layer, and then 1000 Exposing the oxide film to D2 gas by exposing it to a D2 gas in a high-temperature atmosphere of not less than ℃.

(8) In a method of manufacturing a semiconductor device having a structure in which a polycrystalline silicon film is laminated on a surface of a semiconductor substrate or a surface of a semiconductor layer via an oxide film, an oxide film is formed on the surface of the semiconductor substrate or the surface of the semiconductor layer. Forming a;
And then depositing a polycrystalline silicon film by a CVD method using a gas containing a compound of D atoms and Si atoms as a source gas.

(9) In a method of manufacturing a semiconductor device, a step of forming a thermal oxide film on a surface of a semiconductor substrate or a surface of a semiconductor layer, a step of depositing a polycrystalline silicon film, and a step of depositing D atoms and Si atoms Depositing a silicon oxide film by a CVD method using a gas containing a compound as a source gas.

(10) In a method of manufacturing a semiconductor device, a step of forming an oxide film on a surface of a semiconductor substrate or a surface of a semiconductor layer, and then a step of depositing a polycrystalline silicon film;
Next, a step of forming a CVD silicon oxide film, and then exposing to a gas containing a mixed gas of D atoms and N atoms to obtain a CV
Introducing D into the D silicon oxide film.

(11) In a method of manufacturing a semiconductor device, a step of forming an oxide film on a surface of a semiconductor substrate or a surface of a semiconductor layer, a step of forming a polycrystalline silicon film on the oxide film, and then D2O are included. Exposure to gas and D in the oxide film
And a step of introducing

(12) In the step of immersing the semiconductor substrate surface in a liquid, the method is characterized in that the semiconductor substrate surface is immersed in a liquid containing D atoms and fluorine atoms to attach D atoms to the surface of the semiconductor substrate.

(13) In a method of manufacturing a semiconductor device including a step of forming an oxide film on a surface of a semiconductor substrate or a surface of a semiconductor layer, when forming the oxide film, D2 gas and O
The method is characterized in that the surface of the semiconductor substrate or the surface of the semiconductor film is exposed to a gas obtained by mixing two gases and burning D2.

(14) In (1) to (11), the oxide film formed on the surface of the semiconductor substrate or the surface of the semiconductor layer is a gate oxide film.

(15) In (4) to (11), when forming an oxide film, thermal oxidation using a gas containing heavy water (D 2 O) as a raw material or thermal oxidation in active D atoms (D *) .

(16) In any of (9) to (11), a polycrystalline silicon film is deposited by a CVD method using a gas containing a compound of D atoms and Si atoms as a source gas when forming the polycrystalline silicon film.

(Action) The present inventors have studied in detail the mechanism of dielectric breakdown of the gate oxide film and the mechanism of generation of stress leak current. As a result, it has been found that the breakdown mechanism of the gate oxide film and the generation mechanism of the stress leak current are governed by two common mechanisms.

One of them is a dangling bond of silicon formed by breaking an Si—H bond in the film by electrons injected into the gate oxide film.

[0025]

(Equation 1)

Is the cause. The other is due to dangling bonds of silicon formed by breaking weak Si—O bonds in the film. Dielectric breakdown of the gate oxide film is caused by trivalent silicon atoms formed by trapping holes in these silicon dangling bonds.

[0027]

(Equation 2)

When the structure is connected from the silicon substrate to the gate electrode, the connection portion serves as a leak path for electrons, causing dielectric breakdown. On the other hand, in the case of the stress leak current, the dangling bond of silicon by the above-described mechanism located substantially at the center of the gate oxide film acts as a “stepping stone” when tunneling. Therefore, it is a necessary condition for obtaining a gate oxide film having high electrical reliability that a dangling bond of silicon cannot be formed over the entire region in the thickness direction of the gate oxide film.

The present inventors have also clarified that the amount of Si—H bond and the amount of weak Si—O bond are not determined independently, but exist in the film in proportion to each other. I made it. That is, by reducing the amount of Si—H bonds,
It has been found that the amount of weak SiO bonds can be reduced at the same time, and thus a gate oxide film with extremely high electrical reliability can be realized.

According to the present invention, the Si—H bond is formed over the entire region in the thickness direction and the surface direction in the gate oxide film.
By substituting the coupling, a highly reliable gate oxide film is realized.

It is known that post-annealing (900 ° C., 30 minutes) in a D 2 atmosphere after formation of a gate electrode is effective for suppressing the generation of interface state of a MOSFET (NSSaks and RWRendell, IEEE Tranns). .vol.N
S-39, pp. 2220-2229, 1992). However, only by simple annealing after the formation of the MOSFET, the introduction of D atoms into the gate oxide film is partial and the absolute amount of the introduction is small. It is not enough to improve the resistance of the steel.

Therefore, the present invention is characterized in that H atoms are eliminated at the same time as introducing D atoms in the pre-oxidation treatment, during the formation of the gate oxide film, and in the processes after the formation of the gate oxide film. This is intended to reduce the amount of dangling bonds in silicon formed by breaking Si—H bonds by electrons injected into the gate oxide film.

According to the present invention, it is possible to surely solve the serious drawbacks of the deterioration of the gate oxide film quality and the inefficiency in determining the process used in the product, which could not be solved by the prior art.

As described above, in the conventional gate oxide film forming method, various oxide films are formed by changing parameters such as a forming temperature and a forming atmosphere, and their electrical characteristics are evaluated to determine a condition satisfying the specifications. Optimal conditions have been determined by empirical methods of using. However, in the current situation where the types of products are diversified and the generations are being changed rapidly, the setting of conditions by the empirical method as described above is extremely inefficient and seriously increases the product cost. Disadvantages.

On the other hand, in the present invention, in all the processes in which the introduction of H atoms is expected (the pre-oxidation treatment, the process at the time of forming the gate oxide film, and the processes after the gate oxide film is formed)
By replacing H atoms with D atoms,
It is possible to prevent dangling bonds from occurring in silicon caused by cutting Si-H bonds by electrons injected into the gate oxide film. In this case, it is possible to uniformly improve the electrical reliability of the gate oxide film without having to set conditions by an empirical method.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
FIG. 15 is a cross-sectional view showing a manufacturing step of the n-channel MOS transistor according to the embodiment.

First, as shown in FIG. 1A, after an element isolation insulating film 12 was formed on the surface of a p-type silicon substrate 11, the substrate surface was thermally oxidized to form a gate oxide film 13. This gate oxide film was formed by thermal oxidation using D2 O gas as a raw material. Specifically, outside the gate oxidation furnace, D2 O is bubbled into the furnace using N2 gas as a carrier gas, and the silicon surface is exposed to D2 O gas.

At this time, D atoms are not introduced after the formation of the gate electrode, but are introduced at the time of forming the gate oxide film. The introduction amount was sufficient over the entire area in the direction.

Next, as shown in FIG. 1B, a polysilicon film 14 is deposited on the entire surface, and this is
At the same time, selective etching is performed on the gate electrode pattern. Subsequently, after forming a side wall insulating film 15 on the gate side wall, impurities are ion-implanted into the substrate 11 using the gate electrode as a mask to form an n-type diffusion layer (source / drain region) 16 (16a, 16a).
b) was formed.

Next, as shown in FIG. 1C, after an interlayer insulating film 17 was deposited on the entire surface by CVD, contact holes were provided corresponding to the gate, source and drain. Then, after depositing an Al film by sputtering, these were patterned to form a gate electrode 21, a source electrode 22, and a drain electrode 23.

In the MOS transistor of the present embodiment thus obtained, the gate oxide film 13 is formed by thermal oxidation using D 2 O gas as a raw material.
3, the amount of dangling bonds in silicon can be reduced, so that the cause of dielectric breakdown and stress leak can be eliminated, and the electrical reliability of the gate oxide film 13 can be improved. . In addition, it is not necessary to determine the optimum conditions by an empirical method, and D2O gas may be simply used as an atmosphere gas for thermal oxidation. Therefore, it is possible to improve the device reliability of the MOS transistor and reduce the manufacturing cost.

Here, the effects of the present invention will be described using experimental results.

FIG. 2 shows a gate oxide film (designated as DryO 2 oxidation) formed in a dry oxygen atmosphere, a gate oxide film (designated as Wet oxidation) formed in a hydrogen combustion atmosphere, and a deuterated hydroxide film (designated as D 2 O bubbling). 2) shows a Weibull plot of a MOS capacitor having the following expression: In this plot, the steeper the distribution in the right direction along the horizontal axis, the better the gate oxide film has better dielectric breakdown characteristics.

The vertical axis indicates the cumulative failure rate. The horizontal axis represents the total amount of electrons (QBD) that passed through the gate oxide film before the dielectric breakdown occurred. In the experiment, the gate current density (J
g) is a constant current stress test, Jg = 0.1
The test was performed under the condition of A / cm ² . Further, electrons are injected in a direction from the gate electrode toward the silicon substrate.

When electrons are injected from the gate electrode toward the substrate, QBD decreases as the thickness of the gate oxide film decreases. It is generally known that when a wet oxide film and a dry oxide film are compared with the same thickness, the dry oxide film has a smaller QBD. In FIG. 2, the film thickness is 6.8 nm.
The distribution of QBD in the Wet oxide film of 5.8 nm
The reason why the distribution is shifted to the right as compared with that in the O2 oxide film is as described above.

The distribution of QBD in the D 2 O oxide film is as follows, although the oxide film thickness is as small as 5.2 nm,
It shows a significantly better distribution than that of 2. Also, from the distribution of QBD in the 6.8 nm-thick wet oxide film, the D2O oxide film has a 50% QBD
(In the vertical axis, ln {-ln (1-50 / 100)} =-0.3665) becomes smaller. However, it is clear that the distribution of QBD is sharpened by performing gate oxidation using D2O.

As described above, the D 2 O oxidation has a remarkable effect not only on enhancing the average value of QBD but also on steepening the distribution of QBD as an effect of strengthening the gate oxide film. .

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
FIG. 15 is a cross-sectional view showing a manufacturing step of the n-channel MOS transistor according to the embodiment. The same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

This embodiment is different from the first embodiment in that
This is an attempt to further introduce D into the gate oxide film. That is, in the present embodiment, first, as shown in FIG.
Similarly to the embodiment, a gate oxide film 13 is formed on the surface of the substrate 11 by thermal oxidation using D2 O gas as a raw material.

Next, as shown in FIG. 3B, D is introduced into the gate oxide film 13 by ion implantation of D + ions.

Thereafter, similarly to the first embodiment, the formation of the polysilicon film 14, the gate patterning, the formation of the sidewall insulating film 15, the formation of the source / drain diffusion layers 16,
By forming the interlayer insulating film 17 and the electrodes 21, 22, 23, an n-channel MOS transistor is completed.

In the MOS transistor of the present embodiment, the ion implantation of D + ions into the gate oxide film 13 formed in the same manner as in the first embodiment is performed, so that -H bonds can be reduced. Therefore, the electrical reliability of the gate oxide film 13 can be further improved.

If the Si—H bonds in the gate oxide film 13 can be sufficiently reduced only by the ion implantation of D + ions, it is not always necessary to use the D 2 O gas for forming the gate oxide film Thermal oxidation in an oxidizing atmosphere may be performed. By implanting D ions, the bond between Si and H contained in the oxide film can be efficiently cut using the high energy of D ions. Further, since the subsequent D ions also have high energy, the dangling bonds of Si remaining after H is removed can be efficiently terminated. In addition, it can be said that the elimination of H utilizes the sputtering effect by ion implantation.

(Third Embodiment) FIG. 4 shows a third embodiment of the present invention.
FIG. 15 is a cross-sectional view showing a manufacturing step of the n-channel MOS transistor according to the embodiment. The same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

This embodiment is intended not only to reduce the Si—H bond at the time of forming the gate oxide film, but also to prevent the Si—H bond from being generated in the gate oxide film in the subsequent steps.

That is, in this embodiment, first, as shown in FIG. 4A, a gate oxide film 13 is formed on the surface of the substrate 11 by thermal oxidation using D 2 O gas as a raw material, as in the first embodiment. Form.

Next, as shown in FIG. 4B, a polysilicon film 14 is deposited on the entire surface. This polysilicon film 1
4 was deposited using a CVD method, and SiD was used as a source gas.
4 or Si2 D6.

Thereafter, after the polysilicon film 14 and the gate oxide film 13 are patterned, the formation of the side wall insulating film 15, the formation of the source / drain diffusion layer 16, and the formation of the interlayer insulating film are performed in the same manner as in the first embodiment. Formation of the film 17, electrodes 21,
By forming 22 and 23, an n-channel MOS
The transistor is completed.

In the MOS transistor according to the present embodiment, the gate oxide film 13 is formed by thermal oxidation using D 2 O gas as a raw material.
-H bonds can be reduced, and the same effect as in the first embodiment can be obtained. In addition to this, in the present embodiment, Si
Since the polysilicon film 14 is formed by the CVD method using D4 or Si2 D6 as a source gas, generation of Si-H bonds in the gate oxide film 13 during formation of the polysilicon film 14 is prevented. be able to.
Further, when D atoms are solid-phase diffused from the polysilicon film 14 to the gate oxide film by a thermal process performed after the deposition of the polysilicon film 14, the D atom concentration in the gate oxide film can be further increased. Therefore, the electrical reliability of the gate oxide film 13 can be further improved.

From the viewpoint of suppressing the generation of Si—H bonds in the processes after the formation of the gate oxide film 13,
The present invention can be applied to the interlayer insulating film 17. That is,
By depositing a silicon oxide film (interlayer insulating film) 17 by a CVD method using a gas containing a compound of D atoms and Si atoms as a source gas, from the same discussion, the gate oxide film 13 in the formation of the interlayer insulating film 17 is formed. Can be reduced, and can be added to the gate oxide film.

(Fourth Embodiment) FIG. 5 shows a fourth embodiment of the present invention.
FIG. 15 is a cross-sectional view showing a manufacturing step of the n-channel MOS transistor according to the embodiment. The same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, N atoms are introduced together with D atoms into the gate oxide film. That is, in this embodiment, first, as shown in FIG. 5A, a gate oxide film 13 is formed on the surface of the substrate 11 by thermal oxidation using D2 O gas as a raw material, as in the first embodiment.

Next, as shown in FIG. 5B, the substrate surface is exposed to ND 3 gas to introduce N atoms and D atoms into the gate oxide film 13. Thereby, the gate oxide film 13 is substantially transformed into the SiNO film 13 '.

Thereafter, similarly to the first embodiment, the formation of the polysilicon film 14, the gate patterning, the formation of the sidewall insulating film 15, the formation of the source / drain diffusion layer 16,
By forming the interlayer insulating film 17 and the electrodes 21, 22, 23, an n-channel MOS transistor is completed.

In the MOS transistor of the present embodiment, since the gate oxide film 13 is formed by thermal oxidation using D 2 O gas as a raw material, the Si in the gate oxide film 13
-H bonds can be reduced, and the same effect as in the first embodiment can be obtained. In addition, in the present embodiment, by exposing the gate oxide film 13 to the ND3 gas to introduce N atoms and D atoms, the Si--H bonds can be further reduced, and the electric conductivity of the gate oxide film 13 can be further increased. Reliability can be improved.

(Fifth Embodiment) FIG. 6 shows a fifth embodiment of the present invention.
FIG. 15 is a cross-sectional view showing a manufacturing step of the n-channel MOS transistor according to the embodiment. The same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, a gate oxide film is formed using active O atoms and D atoms. That is, in the present embodiment, as shown in FIG.
A gate oxide film 13 is formed by exposing to atoms (O *) and D atoms (D *) and thermally oxidizing them.

As a means for activating O atoms and D atoms, D 2 O gas is introduced into a region other than the chamber where the substrate to be processed is placed, and microwave discharge or plasma discharge is generated in this region. To generate O and D radicals,
These may be introduced into the chamber.

The steps after the formation of the gate oxide film 13 may be the same as those in the first embodiment. Further, the process of forming a gate oxide film according to the present embodiment can be applied to the formation of the gate oxide film according to the second to fourth embodiments described above.

Even with such a method, the same effects as those of the first embodiment can be obtained.

The present invention is not limited to the above embodiments. The gist of the present invention is that H atoms are eliminated at the same time as D atoms are introduced in each process relating to gate oxide film formation. From such a viewpoint, in the step of immersing the silicon substrate in a liquid as a pretreatment of the surface of the silicon substrate, the silicon substrate may be immersed in a liquid containing D atoms and fluorine atoms to attach the D atoms to the substrate surface. Good. Also, generally, diluted hydrofluoric acid (dilute H
It is also effective to use a rare DF in the preprocessing using F). Further, it is also effective to perform D2 annealing at a high temperature exceeding 1000 ° C. where the viscous flow of the gate oxide film occurs. It is also effective to expose the wafer surface to plasma in which D ions or D * are generated to introduce D atoms into the gate oxide film. In this case, the dangling bond on the substrate surface is terminated by D, and since this termination is stable throughout the oxidation process, the introduction of H can be eliminated.

In forming the gate oxide film, D
2 gas and O2 gas may be mixed, and the surface of the silicon substrate may be exposed to a gas obtained by burning D2. further,
The oxide film is not necessarily limited to the gate oxide film, but can be applied to a thin oxide film which is required to have a large dielectric breakdown resistance. That is, the present invention can be applied not only to MOS transistors but also to various semiconductor devices. Further, the present invention is not limited to an oxide film formed directly on a substrate, and can be applied to an oxide film formed on a semiconductor film such as SOI.
In addition, various modifications can be made without departing from the scope of the present invention.

[0074]

As described above in detail, according to the present invention, H is introduced simultaneously with the introduction of D atoms in the pre-oxidation treatment, the formation of the gate oxide film, and the processes after the formation of the gate oxide film.
By eliminating the atoms, generation of dangling bonds of silicon atoms due to electrons injected into the gate oxide film can be suppressed. Therefore, a thin gate oxide film having a high dielectric breakdown resistance and a suppressed stress leak current can be reliably realized.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a manufacturing process of a MOS transistor according to a first embodiment.

FIG. 2 shows an MO having a gate oxide film formed by various methods.
The figure which shows the Weibull plot of S capacitor.

FIG. 3 is a sectional view showing a manufacturing process of the MOS transistor according to the second embodiment.

FIG. 4 is a sectional view showing a manufacturing process of the MOS transistor according to the third embodiment.

FIG. 5 is a sectional view showing a manufacturing process of a MOS transistor according to a fourth embodiment.

FIG. 6 is a sectional view showing a manufacturing step of a MOS transistor according to a fifth embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... p-type silicon substrate 12 ... element isolation insulating film 13 ... gate oxide film 14 ... polysilicon film 15 ... side wall oxide film 16 ... source / drain region 17 ... interlayer insulating film 20 ... Al film 21 ... gate electrode 22 ... source electrode 23 ... Drain electrode

Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01L 29/792

Claims (3)

[Claims] 2. A semiconductor device comprising: an oxide film containing deuterium (D) atoms formed on a surface of a semiconductor substrate or a surface of a semiconductor layer in all regions in a film thickness direction and a surface direction. 2. A method of manufacturing a semiconductor device, comprising the step of forming an oxide film on a surface of a semiconductor substrate or a surface of a semiconductor layer, wherein the oxide film is formed by thermal oxidation using a gas containing heavy water (D2 O) as a raw material. A method of manufacturing a semiconductor device. A step of forming an oxide film on the surface of the semiconductor substrate or the surface of the semiconductor layer; and a step of exposing to a gas containing a compound of D atoms and nitrogen atoms to introduce D into the oxide film. A method for manufacturing a semiconductor device, comprising: