JP2006269641A - Semiconductor device and method for manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain high channel mobility in a p channel MOS electric field effect transistor using a silicon carbide substrate. <P>SOLUTION: This semiconductor device is provided with a semiconductor substrate where a region constituted of n-type silicon carbide is formed, a gate oxide film formed on the n-type region of the semiconductor substrate, a gate electrode formed on the gate oxide film and a source/drain region constituted of a p-type impurity region configuring a transistor arranged adjacently to the gate oxide film and the gate electrode. In this case, hydrogen or hydroxyl group(OH) in extents ranging from 1×10<SP>19</SP>piece cm<SP>-3</SP>to 1×10<SP>20</SP>piece cm<SP>-3</SP>are contained in the gate oxide film. Also, the gate oxidation film is formed by carrying out thermal oxidation in an atmosphere containing H<SB>2</SB>O (water). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor device which is a P-channel type metal-oxide-semiconductor (MOS) field effect transistor fabricated on a silicon carbide substrate, and a manufacturing method thereof, in particular, a semiconductor device with optimized gate oxide film formation method and It relates to the manufacturing method.

Many inventions related to MOS field effect transistors using a silicon carbide substrate have been disclosed. Most of them relate to so-called N channel MOS field effect transistors that use a P-type substrate and allow electrons to flow through a channel inverted to an N-type. is there.
An example in which silicon carbide is used as a P-channel MOS field effect transistor has not been disclosed so far.

  For example, in Patent Document 1 below, in order to reduce the interface state density of a thermal oxide film formation word of a silicon carbide semiconductor device, a silicon oxide film is formed by pyrogenic oxidation in which (1) thermal oxidation is performed by introducing hydrogen and oxygen. In the method for forming a thermal oxide film, the flow rate ratio between hydrogen and oxygen is set to a flow rate ratio in which the flow rate of hydrogen is greater than 1: 1, or (2) cooling after oxidation is performed in an atmosphere containing hydrogen atoms, Disclosed is a method for forming a thermal oxide film in a silicon carbide semiconductor device in which the cooling rate is in the range of 0.3 to 3 ° C./min, or (3) the temperature for taking out after oxidation and cooling is 900 ° C. or less. However, this relates to an N-channel MOS field effect transistor, and there is no description about the P-channel.

There are only a few reports on academic papers. For example, the following Non-Patent Document 1 shows the result of a P-channel MOS field effect transistor using 6H—SiC. Gate oxidation is performed in wet O ₂ , and a channel mobility of 4.7 cm ² / Vs is obtained.
In this non-patent document 1, there is no description about the concentration of hydrogen or hydroxyl group in the gate oxide film, and there is no description about the concentration of H ₂ O (water) at the time of oxidation in wet O _2. It lacks sex.
JP 11-31691 A Man Pio Lam et al “Transactionson Electron Devices” IEEE, Vol. 46, No. 3, March 1999, p. 546

In general, an oxide film-silicon carbide interface using a silicon carbide substrate has a problem of high interface state density. Furthermore, in a P-channel MOS field effect transistor, the mobility becomes low because the carriers become holes. Due to these factors, the channel mobility of the P-channel MOS field effect transistor was only about ˜5 cm ² / Vs.
The present invention has been proposed in view of the above, and has high channel mobility in a semiconductor device using a silicon carbide substrate by optimizing the structure of the P-channel MOS field effect transistor and the method of manufacturing the gate oxide film. It is an object to provide a semiconductor device which is a transistor and a manufacturing method thereof.

In view of the above, the present invention
1) a semiconductor substrate in which a region made of N-type silicon carbide is formed, a gate oxide film formed on the N-type region of the semiconductor substrate, a gate electrode formed on the gate oxide film, and the gate In a semiconductor device having a source and drain regions composed of P-type impurity regions constituting a transistor arranged adjacent to an oxide film and a gate electrode, 1 × 10 ¹⁹ cm ⁻³ to 1 × in the gate oxide film Semiconductor device characterized by containing hydrogen or hydroxyl group (OH) in the range of 10 ²⁰ cm ⁻³ 2) A semiconductor substrate in which a region made of N-type silicon carbide is formed, and an N-type region of the semiconductor substrate A gate oxide film formed on the gate oxide film, a gate electrode formed on the gate oxide film, and a source and drain made of a P-type impurity region constituting a transistor adjacent to the gate oxide film and the gate electrode. In the semiconductor device having the emission region, that hydrogen or hydroxyl in the range of the gate oxide film and 1 × ^{10 20} pieces at the interface of the semiconductor regions ^cm -3 ^~1 × ^{10 22} atoms ^{cm -3} (OH) is present Characteristic semiconductor device 3) The concentration of P-type impurities in the source and / or drain implanted with Al (aluminum) or B (boron) is 1 × 10 ¹⁹ cm ⁻³ to 1 × 10 ²¹ cm ^−3. A semiconductor device as described in 1) or 2) above is provided.

In addition, the present invention
4) a semiconductor substrate in which a region made of N-type silicon carbide is formed, a gate oxide film formed on the N-type region of the semiconductor substrate, a gate electrode formed on the gate oxide film, In a method of manufacturing a semiconductor device having a source and drain regions composed of P-type impurity regions constituting a transistor adjacent to a gate oxide film and a gate electrode, thermal oxidation is performed in an atmosphere containing H ₂ O (water). A method of manufacturing a semiconductor device, comprising forming a gate oxide film.
5) a semiconductor substrate in which a region made of N-type silicon carbide is formed, a gate oxide film formed on the N-type region of the semiconductor substrate, a gate electrode formed on the gate oxide film, In a method of manufacturing a semiconductor device having a source and a drain region composed of a P-type impurity region constituting a transistor adjacent to a gate oxide film and a gate electrode, H ₂ (hydrogen) or H _A method for manufacturing a semiconductor device, wherein heat treatment is performed in an atmosphere containing ₂ O (water).
6) The above 4) or 5), wherein the atmosphere containing H ₂ O comprises H ₂ O, oxygen, and an inert gas, and the H ₂ O concentration is adjusted in the range of 10 to 100% (less than). 7) The H ₂ O (water) gas is generated by the reaction of H ₂ (hydrogen) gas and O ₂ (oxygen) gas in the atmosphere where the semiconductor substrate is placed. 8. A method of manufacturing a semiconductor device according to any one of 4) to 6) above, wherein 8) a flow rate [H ₂ ] of H ₂ (hydrogen) gas, and a flow rate [O ₂ ] of O ₂ (oxygen) gas. ] Is adjusted in the range of [O ₂ ] / [H ₂ ] = 0.1 to 100. 9) The method for manufacturing a semiconductor device according to 7) above, wherein the oxidation temperature of the semiconductor substrate is 1000 ° Any of 4) to 8) above, wherein the temperature is adjusted to a range of C to 1250 ° C. 10) The concentration of the P-type impurity in the source and / or drain implanted with Al (aluminum) or B (boron) is 1 × 10 ¹⁹ cm ⁻³ to 1 × 10 ²¹ cm ^−3. 11) The method of manufacturing a semiconductor device according to any one of 4) to 9) above, wherein after forming an electrode metal in the source and / or drain region, the temperature is in the range of 800 ° C. to 1100 ° C. The method of manufacturing a semiconductor device according to any one of 4) to 10) above, wherein the heat treatment is performed at a temperature. 12) 1 × 10 ¹⁹ cm ⁻³ to 1 × 10 ²⁰ cm ^{− in the} gate oxide film. ³ in the range of hydrogen or a hydroxy 1 × ^{10 20} atoms ^cm -3 to 1 × ^{10 22} atoms ^{cm -3} range of hydrogen or hydroxyl at the interface or to include (OH) or the gate oxide film and the semiconductor region (OH) To exist To provide a method of manufacturing a semiconductor device according to any one of 4) to 11), characterized.

  The present invention has been proposed in view of the above, and the semiconductor device and the manufacturing method thereof according to the present invention are optimized for the structure of the P-channel MOS field-effect transistor and the manufacturing method of the gate oxide film in the semiconductor device using the silicon carbide substrate. Thus, a transistor having high channel mobility can be provided.

  Embodiments of the present invention will be described below in detail with reference to tables and drawings. In addition, the following description is for making an understanding of this invention easy, and is not restrict | limited to this. That is, modifications, embodiments, and other examples based on the technical idea of the present invention are included in the present invention.

The N-type silicon carbide substrate 1 of FIG. 1A (4H—SiC, impurity concentration: 5 × 10 ¹⁵ cm ⁻³ ) is subjected to normal RCA cleaning, and then the N-type silicon carbide substrate 1 is aligned for photolithography. The mark was formed by RIE (Reactive Ion Etching). Next, as shown in FIG. 1B, an ion implantation mask 4 for the source region or the drain region was formed of a thermal oxide film or a SiO ₂ film by a CVD (Chemical Vapor Deposition) method.

In this example, an LTO (Low Temperature Oxide) film was used as an ion implantation mask as shown in FIG. The LTO film was formed by reacting silane and oxygen at 400 ° C. to 800 ° C. to deposit silicon dioxide on the N-type silicon carbide substrate 1. Next, after forming the source / drain regions by photolithography, the LTO was etched with HF (hydrofluoric acid) to open the source region or drain region into which ions were implanted.
Next, in order to form the source 3 or the drain 4 shown in FIG. 1B, ions of aluminum or boron are implanted at 500 ° C. to a depth of 0.5 μm. In this example, (Al) aluminum was used to form an impurity concentration of 1 × 10 ²⁰ cm ⁻³ by multistage implantation.

The impurity element may be B (boron). In order to sufficiently reduce the contact resistance to the source / drain, an impurity concentration of 1 × 10 ¹⁹ cm ⁻³ or more is required. When the impurity concentration exceeds 1 × 10 ²¹ cm ⁻³ , the electric breakdown voltage of the gate oxide film is remarkably lowered, so that the impurity concentration in the source / drain region is 1 × 10 ¹⁹ cm ⁻³ to 1 × 10 ^21. It is desirable to set it as the range of piece cm- ³ . Thereafter, activation annealing was performed in an argon atmosphere at 1600 ° C. for 5 minutes.
Next, a gate oxide film 5 was formed by thermal oxidation as shown in FIG. In this embodiment, gate oxidation was performed by several methods to be described later in order to investigate the influence of the gate oxide film formation method.

After that, the gate electrode 6 is formed. As the method, several methods are known as follows.
1) After the polycrystalline polysilicon is formed by the CVD method, P-type polycrystalline silicon is formed by ion implantation of boron or boron fluoride.
2) After forming polycrystalline polysilicon by the CVD method, a SiO ₂ film containing boron is formed by the CVD method or spin coating, and is diffused by heat treatment at 800 ° C. to 1100 ° C. Silicon is formed.
3) P-type polycrystalline silicon is formed by growing diborane while diffusing diborane in polycrystalline silicon by flowing silane and diborane together and performing heat treatment at 600 ° C.
Although there are the above methods, the method 2) is used in this embodiment. If necessary, the above method 1) or 3) can be employed. There is no restriction | limiting in particular in the said method.

Next, a gate electrode was formed by etching P-type polycrystalline silicon or a composite film of a silicide film and a P-type polycrystalline silicon film and a gate oxide film. Subsequently, the oxide film on the source region or the drain region is etched to open a contact hole.
Next, after depositing a metal containing nickel, titanium or aluminum or a laminated film thereof by vapor deposition or sputtering, the metal wiring 7 is formed by RIE or wet etching. In this embodiment, nickel was deposited and then wet etching was performed. Next, heat treatment was applied to form a good ohmic contact, and a MOS field effect transistor was completed.

Table 1 shows the channel mobility of MOS field effect transistors manufactured by changing the gate oxidation conditions. The channel mobility of the sample in which the gate oxide film is formed with dry O ₂ (oxygen) is 10 cm ² / Vs, whereas the channel mobility of the sample in which the gate oxide film is formed in an atmosphere containing H ₂ O is 16 cm ^2. / Vs and greatly improved.
Further, in the sample in which the gate oxide film was formed by dry O ₂ and then re-oxidized in an atmosphere containing H ₂ O, channel mobility of 13 cm ² / Vs was obtained. It can be seen that channel mobility is improved by reoxidation in an atmosphere containing H ₂ O. Similar results are obtained even when the reoxidation atmosphere is H2.
The water concentration contained in the H ₂ O atmosphere used in this example is 25%. If it is less than 10%, the effect of H ₂ O does not appear. The oxidation temperature is 1200 ° C. At 1250 ° C, the quartz tube of the oxidation reactor is damaged, so the upper limit of the oxidation temperature is limited to 1250 ° C. Below 1000 ° C, oxidation hardly proceeds, so the lower limit is limited to 1000 ° C.

これらのチャネル移動度が改善されたサンプルの、ゲート酸化膜中のＨ_２濃度を、２次イオン質量分析法（ＳＩＭＳ：Secondary Ion Mass Spectroscopy）によって測定したところ、酸化膜中に１×１０^１９個ｃｍ^−３以上の水素元素が検出されたサンプルのチャネル移動度が改善されていることがわかった。しかし、１×１０^２０個ｃｍ^−３を超えると、水素による酸化膜の還元が進み、酸化膜の電気耐圧が低下する。
さらに、チャネル移動度が改善されたサンプルの酸化膜−炭化珪素界面においては１×１０^２１個ｃｍ^−３の水素元素が検出された。１×１０^２２個ｃｍ^−３を超えると同様に酸化膜の電気耐圧が低下する。これらの検出される水素量は、水素元素として結合しているか又は水酸基として結合しているかのいずれかと考えられるが、水酸基としても同様に考えることができる。

When the H ₂ concentration in the gate oxide film of these samples with improved channel mobility was measured by secondary ion mass spectrometry (SIMS), 1 × 10 ¹⁹ in the oxide film. It was found that the channel mobility of the sample in which hydrogen element of cm ⁻³ or more was detected was improved. However, if it exceeds 1 × 10 ²⁰ cm ⁻³ , the reduction of the oxide film with hydrogen proceeds, and the electric breakdown voltage of the oxide film decreases.
Further, 1 × 10 ²¹ cm ⁻³ of hydrogen element was detected at the oxide film-silicon carbide interface of the sample with improved channel mobility. When 1 × 10 ²² pieces cm ⁻³ is exceeded, the electric breakdown voltage of the oxide film is similarly lowered. The amount of hydrogen detected can be considered to be either bonded as a hydrogen element or bonded as a hydroxyl group, but can also be considered as a hydroxyl group.

These phenomena are thought to be due to the fact that dangling bonds and carbon clusters in the gate oxide film were passivated by hydrogen elements or hydroxyl groups, and channel mobility was improved. From the above, it can be seen that it is optimal that the gate oxide film contains hydrogen or a hydroxyl group (OH) in the range of 1 × 10 ¹⁹ cm ⁻³ to 1 × 10 ²⁰ cm ⁻³ .
In the above, the optimum concentration of hydrogen or hydroxyl group (OH) in the gate oxide film for improving the channel mobility has been described, but this is not limited to the interface between the gate oxide film and the semiconductor region. The oxide film-semiconductor interface has low integrity, and there are many silicon dangling bonds (dangling bonds) and carbon clusters. Therefore, hydrogen or hydroxyl passivating is promoted, and the concentration at the interface increases. Oxide - In semiconductor interface, 1 two orders of magnitude larger compared to the oxide film, 1 × ^{10 20} atoms ^cm -3 to 1 × ^{10 22} atoms ^{cm -3} range of hydrogen or hydroxyl (OH) is present Sometimes channel mobility was improved.

Then, the vapor of H _{2 O} to warm pure water, which in the case where oxidizing the silicon carbide substrate by flowing an argon gas, to generate of H _{2 O} by combustion of H ₂ and O _2, with argon gas Table 2 shows the results of channel mobility when the silicon carbide substrate was oxidized by flowing the current.
In the present example was carried out in _{O 2} flow rate _{[O 2]} and the ratio between the flow rate of _{H 2 [H 2],} the oxidation under the conditions of _{[O 2] / [H 2} ] = 3.0. It can be seen that the generation of H ₂ O by burning H ₂ and O ₂ suppresses the mixing of impurities, which is effective in improving channel mobility.
The ratio of the flow rate [H ₂ ] of H ₂ (hydrogen) gas and the flow rate [O ₂ ] of O ₂ (oxygen) gas is in the range of [O ₂ ] / [H ₂ ] = 0.1-100. A similar result was obtained by adjusting with.

次に、ソース・ドレイン領域へのコンタクト電極へのアニールの効果を表３に示す。アニールなしのサンプルは大きく移動度が低下することがわかる。これは、Ｐ型のソース・ドレイン領域へのコンタクト抵抗が大きく、チャネル部の抵抗と比較して無視できないほど大きくなったためであると考えられる。
コンタクトアニールを施すことにより、ソース・ドレイン領域へのコンタクト抵抗は十分下げることができる。本実実施例では、熱処理を不活性ガスであるＡｒ中で行っているが、Ｈｅを用いてもよい。また、不活性ガスとＨ_２（水素）の混合ガスを用いても良い。

Next, Table 3 shows the effect of annealing the contact electrodes on the source / drain regions. It can be seen that the mobility of the sample without annealing is greatly reduced. This is presumably because the contact resistance to the P-type source / drain region is large and is not negligible compared to the resistance of the channel portion.
By performing contact annealing, the contact resistance to the source / drain regions can be sufficiently reduced. In this embodiment, the heat treatment is performed in Ar, which is an inert gas, but He may be used. It is also possible to use a mixed gas of inert gas and H _{2 (hydrogen).}

When the annealing temperature exceeds 1100 ° C., the damage due to the temperature increases and the passivation due to hydrogen is impaired, so that the channel mobility is reduced to 10 cm ² / Vs. Further, when the temperature is less than 800 ° C., the reaction between the metal and silicon carbide does not sufficiently proceed, so that the contact resistance increases, and the channel mobility decreases to 5 cm ² / Vs or less. The annealing time is in the range of 30 seconds to 30 minutes, preferably 1 minute to 5 minutes.
From the above, it can be said that it is desirable to perform heat treatment at a temperature in the range of 800 ° C. to 1100 ° C. after forming the electrode metal in the source and / or drain regions.

The actions (functions) and effects achieved by the present invention are summarized as follows.
In the P-channel field effect transistor formed in the first 1: N-type silicon carbide region, the channel mobility could be improved by controlling the concentration of hydrogen or hydroxyl group in the gate oxide film.
Second: In the P-channel field effect transistor formed in the N-type silicon carbide region, the channel mobility is controlled by controlling the concentration of hydrogen or hydroxyl group in the gate oxide film, particularly at the oxide film-silicon carbide interface. I was able to improve.
Third: In the P-channel field effect transistor formed in the N-type silicon carbide region, the channel mobility can be improved by forming the gate oxide film in an atmosphere containing water.
Fourth: In a P-channel field effect transistor formed in an N-type silicon carbide region, after forming a gate oxide film, heat treatment is performed in an atmosphere containing H ₂ or H ₂ O, thereby improving channel mobility. I was able to.
Fifth: In addition to the features of the third or fourth invention, the atmosphere containing H ₂ O is composed of H ₂ O, O ₂ and an inert gas, and H ₂ O is predetermined from 10% to 100%. The channel mobility could be improved by using an atmosphere having a high concentration.
Sixth: In addition to the characteristics of the third to fifth inventions, the atmosphere containing H ₂ O is generated by the combustion of H ₂ and O ₂ , thereby suppressing the mixing of impurities and improving the channel mobility. I was able to.
Seventh: In addition to the features of the sixth invention, channel mobility is improved by setting the ratio of the flow rate of O ₂ and H ₂ to [O ₂ ] / [H ₂ ] = 0.1-100. I was able to.
Eighth: In addition to the features of the first to seventh inventions, channel mobility is improved by making the oxidation temperature within a predetermined temperature range of 1000 ° C. to 1250 ° C. I was able to.
Ninth: In addition to the features of the first to eighth inventions, by setting the impurity concentration of the source / drain to 1 × 10 ¹⁹ cm ⁻³ to 1 × 10 ²¹ cm ⁻³ , it has a sufficiently low contact resistance, In addition, the gate oxide film can have a sufficiently high withstand voltage, and the channel mobility can be improved.
10th: In addition to the features of the first to ninth inventions, the contact resistance is reduced by heat-treating the source / drain contact electrodes in a temperature range of 800 ° C. to 1000 ° C. for a predetermined time, The channel mobility could be improved.

  A semiconductor device and a manufacturing method thereof according to the present invention are a transistor having a high channel mobility in a semiconductor device using a silicon carbide substrate by optimizing the structure of a P-channel MOS field effect transistor and the manufacturing method of a gate oxide film. Therefore, it is suitable for a MOS field effect transistor.

FIGS. 4A and 4B are explanatory views showing a method for manufacturing a MOS field effect transistor.

Explanation of symbols

1 N-type silicon carbide substrate 2 Mask for ion implantation 3 Source 4 Drain 5 Gate oxide film 6 Gate electrode 7 Metal wiring

Claims (12)

A semiconductor substrate having a region made of N-type silicon carbide, a gate oxide film formed on the N-type region of the semiconductor substrate, a gate electrode formed on the gate oxide film, and the gate oxide film 1 × 10 ¹⁹ cm ⁻³ to 1 × 10 ^{20 in the} gate oxide film in a semiconductor device having a source and drain region composed of a P-type impurity region constituting a transistor disposed adjacent to the gate electrode. A semiconductor device including hydrogen or a hydroxyl group (OH) in the range of ³ cm ⁻³ . A semiconductor substrate having a region made of N-type silicon carbide, a gate oxide film formed on the N-type region of the semiconductor substrate, a gate electrode formed on the gate oxide film, and the gate oxidation In a semiconductor device having a source and drain region composed of a P-type impurity region constituting a transistor adjacent to a film and a gate electrode, 1 × 10 ²⁰ cm ⁻³ to 1 × at the interface between the gate oxide film and the semiconductor region 10. A semiconductor device characterized in that hydrogen or a hydroxyl group (OH) in a range of 10 ²² cm ⁻³ exists. The concentration of the P-type impurity in the source and / or drain implanted with Al (aluminum) or B (boron) is 1 × 10 ¹⁹ cm ⁻³ to 1 × 10 ²¹ cm ^−3. Or the semiconductor device of 2. A semiconductor substrate having a region made of N-type silicon carbide, a gate oxide film formed on the N-type region of the semiconductor substrate, a gate electrode formed on the gate oxide film, and the gate oxidation In a method of manufacturing a semiconductor device having a source and a drain region composed of a P-type impurity region constituting a transistor adjacent to a film and a gate electrode, gate oxidation is performed by thermal oxidation in an atmosphere containing H ₂ O (water). A method of manufacturing a semiconductor device, comprising forming a film. A semiconductor substrate having a region made of N-type silicon carbide, a gate oxide film formed on the N-type region of the semiconductor substrate, a gate electrode formed on the gate oxide film, and the gate oxidation In a method of manufacturing a semiconductor device having a source and drain region composed of a P-type impurity region constituting a transistor adjacent to a film and a gate electrode, after forming a gate oxide film, H ₂ (hydrogen) or H ₂ O A method for manufacturing a semiconductor device, wherein heat treatment is performed in an atmosphere containing (water). The atmosphere containing H ₂ O is composed of H ₂ O, oxygen, and an inert gas, and the H ₂ O concentration is adjusted in a range of 10 to 100% (less than). A method for manufacturing a semiconductor device. 5. The H ₂ O (water) gas is generated by a reaction of H ₂ (hydrogen) gas and O ₂ (oxygen) gas in an atmosphere in which a semiconductor substrate is placed. 7. A method for manufacturing a semiconductor device according to claim 6. The ratio of the flow rate [H ₂ ] of H ₂ (hydrogen) gas and the flow rate [O ₂ ] of O ₂ (oxygen) gas is adjusted in the range of [O ₂ ] / [H ₂ ] = 0.1-100. A method for manufacturing a semiconductor device according to claim 7.   9. The method of manufacturing a semiconductor device according to claim 4, wherein an oxidation temperature of the semiconductor substrate is adjusted to a range of 1000 [deg.] C. to 1250 [deg.] C. The concentration of P-type impurities in the source and drain into which Al (aluminum) or B (boron) is implanted is 1 × 10 ¹⁹ cm ⁻³ to 1 × 10 ²¹ cm ⁻³ . 10. A method for manufacturing a semiconductor device according to any one of 9 above.   The method for manufacturing a semiconductor device according to claim 4, wherein heat treatment is performed at a temperature in a range of 800 ° C. to 1100 ° C. after forming an electrode metal in the source and / or drain region. . Hydrogen or hydroxyl group (OH) in the range of 1 × 10 ¹⁹ cm ⁻³ to 1 × 10 ²⁰ cm ⁻³ is included in the gate oxide film, or 1 × 10 ^{20 at} the interface between the gate oxide film and the semiconductor region. The method for manufacturing a semiconductor device according to claim 4, wherein hydrogen or a hydroxyl group (OH) in a range of cm ⁻³ to 1 × 10 ²² cm ⁻³ is present.

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