JP3950959B2 - Manufacturing method of semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a MIS (Metal-Insulator-Semiconductor) capacitor or MISFET (Metal-Insulator-Semiconductor-Semiconductor-Metal-Insulator-Semiconductor) on a semiconductor substrate including a silicon carbide region.
By taking steps that can reduce the interface defects (interface states) between the capacitor insulating film or gate insulating film used in Field-Effect-Transistor) and the above semiconductor region, for example, good electrical characteristics can be obtained. The present invention relates to a method of manufacturing a semiconductor device capable of forming a SiC (silicon carbide) transistor.
[0002]
[Prior art]
Silicon carbide (SiC) material is a semiconductor material that has excellent characteristics such as a large band gap, high thermal conductivity, high saturation electron drift velocity, and high breakdown voltage. It is attracting attention as an element material. In order to manufacture such a SiC power device, it is necessary to develop a rectifying element (diode) or a switching element as a basic element which is a constituent element thereof. Among them, a typical switching element is a MISFET, and in particular, a metal-oxide-semiconductor field-effect transistor (MOSFET) whose insulating film is a silicon oxide film is a metal-oxide-semiconductor field-effect transistor (MOSFET). . For MOSFETs, unlike transistors made on other compound semiconductors, silicon oxide films can be formed on SiC substrates by thermal oxidation, just like silicon substrates. A MOSFET can be manufactured by a process.
[0003]
On the other hand, it has been reported that when an oxide film / SiC structure is formed using an oxidation process similar to that for a silicon substrate, interface defects peculiar to the oxide film / SiC interface are formed. Due to this interface defect, the characteristics of the oxide film / SiC interface become inferior, and the channel mobility of the SiC-MOSFET manufactured by the usual thermal oxidation method such as dry oxidation or wet oxidation is not as high as that of the SiC bulk. The electron mobility is extremely lower than the expected value, and it is not practical as a transistor.
[0004]
Since the channel mobility in the current SiC-MOSFET is extremely small, its on-resistance value (R _on ) is extremely higher than the value theoretically expected from its physical property values. In particular, in silicon carbide (4H—SiC) having a crystal structure called 4H, a gate oxide film is formed by a normal thermal oxidation method such as dry oxidation, although the bulk electron mobility is about 900 cm ² / Vs. The channel mobility of the fabricated MOSFET is as extremely low as about 5 to 10 cm ² / Vs. This is considered to be caused by a high interface state density in the vicinity of the conduction band of the channel portion.
[0005]
Recent reports include re-oxidation treatment in a water vapor atmosphere after the formation of a gate oxide film, reference 1 (GY Chung, CC Tin, JR Williams, K. McDonald, RK Chanana, RA Weller, ST Pantelides, LC Feldman, OW Holland. , MK Das and JW Palmour, IEEE Electron Device Lett. 22, 176 (2001).), The re-oxidation treatment in a nitrous oxide (NO) atmosphere improved the channel mobility, and 30-50 cm ² / Vs. It has been reported to improve to a certain extent. However, these values are still small, and it is clear that there is still room for improvement in terms of bulk electron mobility.
[0006]
Therefore, in order to realize a high channel mobility SiC-MOSFET, establishment of a gate oxide film forming method with less generation of interface defects peculiar to the oxide film / SiC interface and a manufacturing process for reducing interface defects peculiar to the oxide film / SiC interface Establishing is an extremely important issue.
[0007]
As such a method for forming a gate oxide film, the present invention proposes an oxidation method using atomic oxygen, but several reports have already been made regarding the oxidation of SiC using atomic oxygen. For example, in Reference 2 (M. Satoh et al., Mat. Sci. Forum 389-393, 1105 (2002)), atomic oxygen in a plasma is caused by flowing a mixed gas of oxygen and argon in a microwave plasma. An oxidation process for producing 6H-SiC has been reported. This oxidation condition is a low temperature of about 200 ° C. and the process pressure is as low as 0.15 Torr (20.0 Pa) or less. However, this oxidation process shows a significant increase in the oxidation rate, and the resulting oxide film has a resistance to oxidation. The voltage characteristics and withstand voltage distribution are similar to those obtained by high-temperature thermal oxidation by a normal dry oxidation method. In addition, the presence of oxidized species (ion species) having a charge as well as neutrality has been confirmed from the spectral spectrum of plasma. The reported oxidation process is oxidation with atomic oxygen, which differs from the present invention in any point of oxidation temperature, pressure range or method of generating atomic oxygen.
[0008]
Further, a post-processing step after the formation of the gate oxide film is reported in, for example, Reference 3 (Y. Maeyama et al., Mat. Sci. Forum 389-393, 997 (2002)). This is performed as a post-processing step after the gate oxide film is formed, and is a manufacturing process in which oxygen radical processing is performed by RF (radio wave) plasma. The reported substrate temperature is 580 ° C. and the pressure is 1 × 10 ⁻⁵ Torr (1.33 × 10 ⁻³ Pa) to 5 × 10 ⁻⁵ Torr (6.65 × 10 ⁻³ Pa). However, Document 3 reports that the interface characteristics deteriorate due to this oxygen radical treatment.
[0009]
In addition, a process using ozone generated by irradiating ultraviolet rays to oxygen molecules is reported in, for example, Reference 4 (VV Afanas'ev et al., Appl. Phys. Lett. 76, 36 (2000)). Yes. In this process, ozone is generated by irradiating oxygen molecules with ultraviolet rays, and this is used to clean the SiC surface. Further, a process is known in which ozone molecules are used as a raw material gas, and atomic oxygen in an excited state is generated by irradiating ultraviolet rays in this reduced pressure state to clean the SiC surface. These are all related to the cleaning process before forming the gate oxide film, and are different from the present invention.
[0010]
[Problems to be solved by the invention]
As described above, in order to realize a high channel mobility SiC-MOSFET, the establishment of a gate oxide film formation method with less generation of interface defects peculiar to the oxide film / SiC interface and reduction of interface defects peculiar to the oxide film / SiC interface are reduced. Establishing a manufacturing process is an extremely important issue.
[0011]
The present invention has been proposed in order to solve the above-described problem, and provides a method for manufacturing a MOS (MIS) type semiconductor device having a reduced interface state density in a semiconductor device using a semiconductor substrate including a SiC region. The purpose is to provide.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, a first invention of the present invention relates to a method of manufacturing a semiconductor device, and a source or drain electrode of an insulated gate transistor or a metal-insulating film-semiconductor is formed on a substrate including a silicon carbide semiconductor region. Forming an electrode in a semiconductor region of a capacitor having a region structure; cleaning a substrate including the semiconductor region; and forming a gate insulating film of the transistor or a capacitor insulating film of the capacitor on the substrate. In manufacturing a semiconductor device including a step, a step of forming an electrode on the gate insulating film or the capacitor insulating film, and a step of forming a lead line of the electrode,
The step of forming the gate insulating film or the capacitor insulating film is performed in an atmosphere containing atomic oxygen whose substrate temperature is set to 1200 ° C. and which is maintained in a pressure range of 1 mTorr (0.133 Pa) to 50 Torr (6.65 kPa). It is characterized by doing.
[0013]
According to a second aspect of the present invention, a MOS or MIS interface having a reduced interface state density is formed using oxidation with atomic oxygen, and the substrate is a silicon carbide substrate , A gate insulating film having a thickness of 1 nm or more is formed in the step of forming a gate insulating film or a capacitor insulating film, and the atmosphere containing atomic oxygen is generated by decomposition of a source gas containing 10% by volume or more of ozone molecules. It is characterized by.
[0014]
The third invention in the present invention is to form a MOS or MIS interface with a reduced interface state density by using oxidation with a high concentration of atomic oxygen. In addition to the second invention, The atmosphere containing atomic oxygen is generated by the decomposition of ozone molecules by ultraviolet rays.
[0015]
According to a fourth aspect of the present invention, the interface is stabilized by annealing to form a MOS or MIS interface with a reduced interface state density. In addition to the invention, after the step of forming the gate insulating film or the capacitor insulating film, the temperature is maintained at a predetermined temperature and at a predetermined pressure in an atmosphere containing an inert gas for a predetermined time. Including a heat treatment step.
[0016]
According to a fifth aspect of the present invention, a MOS or MIS interface having a reduced interface state density is formed by introducing a step of reducing the interface state density after forming the gate oxide film. In addition to any one of the first to fourth inventions, a step of forming the gate insulating film or the capacitor insulating film and a step of forming a lead line for the electrode on the gate insulating film or the capacitor insulating film of the transistor And a heat treatment step of holding at a predetermined temperature and a predetermined pressure in a hydrogen-containing atmosphere for a predetermined time.
[0017]
According to a sixth aspect of the present invention, a MOS or MIS interface having a reduced interface state density is formed by preventing loss of controllability due to contact with outside air. In addition to any of the fifth to fifth aspects of the present invention, the above-described surface cleaning process of the semiconductor region, the above-described gate insulating film or capacitor insulating film forming process, and the subsequent heat treatment process are performed in an apparatus that is shut off from the outside air. It is characterized by being performed continuously.
[0018]
The seventh, eighth or ninth invention of the present invention makes the effect remarkable by using a substrate having a specific plane orientation, and any one of the first to sixth inventions described above. In addition, the plane orientation of the silicon carbide region is (0, 0, 0, -1), (0, 0, 0, 1), or (1, 1, -2, 0) plane. Features.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
According to the method of manufacturing a semiconductor device for forming a gate insulating film in an atmosphere containing atomic oxygen according to the present invention, the step of forming the gate insulating film is performed by using the source or drain electrode of the insulated gate transistor or the metal-insulating film- This is performed after the formation of the electrode of the semiconductor region of the capacitor having the semiconductor region structure. The feature is that, besides containing atomic oxygen, an optimum substrate temperature and atmospheric pressure are set. As for the latter, there is a clear range as an optimum condition, and no reduction in interface state density is observed for those outside this condition. These setting conditions are significantly different from the oxidation conditions of SiC substrates and silicon substrates reported so far by atomic oxygen. Embodiments of the present invention will be described below based on examples.
[0020]
【Example】
The lifetime of the oxidized species in the case of oxidizing the silicon carbide substrate (SiC) with atomic oxygen is significantly different from the lifetime of the oxidized species of oxidation by normal dry oxygen or water vapor. For example, in the oxidation with atomic oxygen, the atomic oxygen decomposed and generated from the raw material gas is likely to be combined, and therefore needs to be supplied to the SiC substrate surface quickly. For this purpose, it is desirable to reduce the process pressure and to lengthen the mean free path of the oxidizing species containing atomic oxygen.
[0021]
An oxidation apparatus used in this process is shown in FIG. FIG. 1 shows a vertical oxidizer 1 that generates ozone from a dry oxygen gas 11 using an ozone generator 2 and supplies it to a high-temperature oxidation furnace 9 to oxidize a semiconductor substrate 10. The inside of the oxidation furnace 9 is maintained in a reduced pressure atmosphere as shown below. The semiconductor substrate 10 is taken into and out of the oxidation furnace 9 by opening the shut-off door 3, but the shut-off door 3 is closed during the process. Further, the pressure is adjusted by the pressure control valve 5, and exhaust is performed by the exhaust device 4.
[0022]
For example, as shown in this embodiment, when the source gas is a mixed gas of ozone and dry oxygen gas, it is known that the actual oxidizing atmosphere contains atomic oxygen decomposed and generated from ozone molecules. In addition to this, since oxygen molecules are present, it is necessary to subtract oxidation by oxygen molecules when discussing oxidation by ozone molecules or atomic oxygen decomposed and generated therefrom.
[0023]
Therefore, first, the result of examining the oxidation under reduced pressure by oxygen gas is shown. FIG. 2 shows the oxide film thickness obtained when N-type 4H—SiC (0, 0, 0, 1) and N-type 4H—SiC (0, 0, 0, −1) were oxidized in oxygen. It is a figure which shows pressure dependence. The substrate temperature is 1200 ° C. and the oxidation time is about 40 minutes. It can be seen that oxidation in oxygen reduces the oxidation rate as the pressure decreases. In particular, on the (0, 0, 0, 1) plane, it can be seen that the oxidation hardly proceeds when the pressure is reduced to about 50 Torr ( 6.65 kPa ).
[0024]
FIG. 3 shows the oxidation rate when 4H—SiC (0, 0, 0, 1) and 4H—SiC (0, 0, 0, −1) are oxidized in a mixed gas atmosphere of ozone and oxygen. It is a figure which shows pressure dependence. Here, the substrate temperature is 1200 ° C., and the ozone concentration in the mixed gas of ozone and oxygen is 10% by volume. Ozone gas, which is a mixed gas of ozone and oxygen, is supplied from the outside using an ozone generator. From FIG. 3, it can be seen that there is a region where the oxidation rate increases as the pressure is reduced, and has a peak in the vicinity of 2 Torr ( 266 Pa ) to 5 Torr ( 665 Pa ). That is, in the case of oxidation using only the oxygen gas described above, the oxidation rate decreases as the pressure is reduced. However, in the oxidation using atomic oxygen generated by the thermal decomposition of ozone molecules, there is a region having the opposite characteristics. As shown in FIG. 2, in the pressure region of 50 Torr (6.65 kPa) or less, oxidation by oxygen hardly occurred. Therefore, in the oxidation of 50 Torr or less by the mixed gas of ozone and oxygen gas, the atomic state It can be said that oxygen is the main oxidizing species.
[0025]
In a pressure region higher than 50 Torr ( 6.65 kPa ), both oxygen and atomic oxygen become oxidizing species. However, if the pressure is too high, the generated atomic oxygen cannot reach the surface. Therefore, a pressure of 50 Torr ( 6.65 kPa ) or less is appropriate for effective oxidation with atomic oxygen.
[0026]
Further, under the oxidation conditions of this embodiment, the oxidation rate decreases when the pressure is 5 Torr or less, and the oxidation rate at 1 Torr ( 133 Pa ) is about half of the oxidation rate at 5 Torr ( 0.665 kPa ). This depends on the absolute number of atomic oxygen decomposed and generated from ozone molecules, and the oxidation rate depends on the ozone concentration. When oxidation was actually performed at an ozone concentration of about 80%, the oxidation rate at a pressure of 5 Torr ( 0.665 kPa ) was about 720 K / h.
[0027]
And the oxidation rate in this 5Torr (0.665kPa), using the above relationship that the rate of oxidation pressure is 1/5 to approximately half, estimated rate of oxidation at a pressure lower than 5Torr (0.665kPa) The results are shown in FIG. In FIG. 4, the pressure is plotted on the horizontal axis, and the oxidation rate at an ozone concentration of 80% is extrapolated from the above relationship. It can be seen that effective oxidation with atomic oxygen is possible up to about 1 mTorr ( 0.133 Pa ) by using ozone with a higher concentration than this. From the above, it was confirmed that the oxidation of SiC with atomic oxygen can be effectively performed in the range of 1 mTorr ( 0.133 Pa ) to 50 Torr ( 6.65 kPa ).
[0028]
The interface state density shown in FIG. 5 obtained by measurement using a MOS capacitor manufactured by oxidizing SiC in the above pressure range will be described. The result of the interface state density obtained from the MOS capacitor is often used as an index for discussing the channel mobility of a transistor in manufacturing an insulated gate semiconductor device.
[0029]
The MOS structure was fabricated by depositing an aluminum electrode on the oxide film and on the back surface of the SiC substrate after forming the gate oxide film. The interface state density (Dit) was evaluated from the high-frequency low-frequency capacitance-voltage (C-V) characteristics of the fabricated MOS capacitor. As the SiC substrate, an N-type 4H—SiC (0, 0, 0, 1) epitaxial substrate (the difference between the acceptor density Na and the donor density Nd is about 5 × 10 ¹⁵ cm ⁻³ ) was used. The substrate temperature during oxidation is 950 ° C. or 1200 ° C. The pressure was 5 Torr ( 0.665 kPa ). A mixed gas of oxygen gas and ozone from an ozone generator was used as the source gas, and the ozone concentration was about 10% by volume. The heat treatment after forming the gate oxide film was performed at 1 atm in a nitrogen gas atmosphere for 30 minutes at the respective gate oxide film formation temperature (950 ° C. or 1200 ° C.). FIG. 5A shows the case where the oxidation temperature is 1200 ° C., and FIG. 5B shows the case where the oxidation temperature is 950 ° C. FIG. 5C is for comparison, and shows the Dit distribution when the formation of the gate oxide film is performed in oxygen gas at 1 atm and 1200 ° C. for the above-described MOS capacitor fabrication. The heat treatment in nitrogen gas is similarly performed (1200 ° C.).
[0030]
First, when the substrate temperature of the oxidation with atomic oxygen in FIG. 5B is 950 ° C., Dit near 0.15 eV from the lower end of the conductor is almost the same as FIG. On the other hand, when oxidation was performed at 1200 ° C. in FIG. 5A, a significant decrease in Dit was confirmed in the range of 0.30 eV from the lower end of the conductor. This indicates that the interface characteristics are not improved when the substrate temperature is low even at the same pressure. That is, it can be seen that by oxidizing at a temperature of 950 ° C. or higher, Dit can be reduced in the oxidation with atomic oxygen. From the above results, in the oxidation of SiC in an atmosphere containing atomic oxygen, a good MOS interface can be formed under the conditions of a pressure of 1 mTorr ( 0.133 Pa ) to 50 Torr ( 6.65 kPa ) and a substrate temperature of 950 ° C. or higher. confirmed.
[0031]
In the above embodiment, an example was shown in which atomic oxygen was generated by thermal decomposition of ozone molecules using a mixed gas of ozone and oxygen gas as the source gas. When atomic oxygen was generated from ozone by photolysis such as ultraviolet rays, a greater improvement in interface characteristics was observed. This seems to be due to the fact that, in addition to the increase in the absolute number of atomic oxygen, excited atomic oxygen is generated that cannot be obtained by thermal decomposition of ozone molecules. FIG. 6 is a diagram showing a cross section of an oxidizer that generates atomic oxygen from ozone by photolysis such as ultraviolet rays. In the apparatus shown here, an ultraviolet irradiation device 6 using an ultraviolet lamp is placed outside the oxidation furnace 9 to irradiate ultraviolet rays through the furnace wall in order to prevent diffusion of impurities. The reduction of Dit was also confirmed when 4H-SiC (0, 0, 0, -1), 4H-SiC (1, 1, -2, 0) surfaces were used.
[0032]
Also, after forming the gate insulating film, heat treatment for 30 minutes in an atmosphere of 0.1 atm and 1200 ° C. containing 80% nitrogen can reduce Dit by 20%, although not shown in the figure. It was.
[0033]
Similarly, after the gate insulating film is formed, heat treatment is performed for 30 minutes in an atmosphere of 1 atm. 800 ° C. containing 4% hydrogen and 96% nitrogen. Dit reduction was seen.
[0034]
In addition, the above-described SiC semiconductor region surface cleaning step, gate insulating film formation step, and subsequent heat treatment step are removed from the surface of the controlled semiconductor region due to the opportunity to come into contact with the outside air, so these are blocked. It is clear that it is desirable to do so continuously in the installed apparatus. Such processing can proceed in one furnace by changing the processing conditions according to the processing. A plurality of furnaces can be used, and an apparatus for this purpose is shown in FIG. FIG. 7 is a schematic view of a continuous processing apparatus. After the semiconductor substrate 10 is degassed in the load lock chamber 17, the semiconductor substrate 10 is cleaned by the cleaning apparatus 7 by the transfer device 16 through the opened load lock door. Then, oxidation is performed in the oxidation apparatus 1, heat treatment after oxidation is performed in the heat treatment apparatus 8, and the process returns to the load lock chamber again and is taken out. Although this control is not shown in the figure, the operation and processing conditions of each device are controlled by a control device using a computer.
[0035]
In the above embodiments, the interface characteristics of the most basic MOS capacitor have been described. However, the invention described in this specification is not limited to a horizontal MOS (MIS) FET, but also a vertical MOS (MIS) FET, an insulation. It is apparent that the present invention can be applied to all semiconductor devices having a gate insulating film forming step such as a gate bipolar transistor (IGBT) and a MOS (MIS) thyristor.
[0036]
【The invention's effect】
Since this invention consists of an above-described structure, there can exist an effect which is demonstrated below.
[0037]
According to the present invention, a step of forming a source or drain electrode of an insulated gate transistor or an electrode of a semiconductor region of a capacitor having a metal-insulating film-semiconductor region structure on a substrate including a semiconductor region, and cleaning the substrate including the semiconductor region Forming a gate insulating film of the transistor or a capacitor insulating film of the capacitor on the substrate, forming an electrode on the gate insulating film or the capacitor insulating film, and the electrode In manufacturing a semiconductor device including a step of forming a lead line, a MOS (MIS) type semiconductor device with a reduced interface state density can be realized.
[0038]
In particular, in the first aspect of the present invention, the step of forming the capacitor insulating film of the gate insulating film or a capacitor, the substrate temperature is set to 1200 ° C., from 1 mTorr (0.133 Pa) 50 Torr of (6.65 kPa) By performing in an atmosphere containing atomic oxygen kept in the pressure range, a MOS or MIS interface with reduced interface state density is formed.
[0039]
Further, in the second and third inventions, the interface state density is reduced by generating an atmosphere containing atomic oxygen by thermal decomposition or ultraviolet decomposition of a source gas containing ozone molecules having a concentration of 10% by volume or more. A MOS or MIS interface is formed.
[0040]
In the fourth and fifth inventions, after the step of forming the gate insulating film or the capacitor insulating film, a predetermined temperature is set in an atmosphere containing an inert gas or an atmosphere containing hydrogen. A MOS or MIS interface with a reduced interface state density is formed by performing a heat treatment process that is held for a predetermined time under pressure.
[0041]
According to a sixth aspect of the invention, in the manufacture of a silicon carbide semiconductor device including the step of forming a gate insulating film or a capacitor insulating film on the semiconductor substrate including the silicon carbide region described above, a step of cleaning the surface of the semiconductor region, By continuously performing the gate insulating film or capacitor insulating film forming process and the subsequent heat treatment process in an apparatus cut off from the outside air, a MOS or MIS interface with a reduced interface state density is formed.
[0042]
In the seventh, eighth or ninth invention, in the manufacture of the silicon carbide semiconductor device described above, the plane orientation of the silicon carbide substrate is (0, 0, 0, −1), (0, 0, 0, By using the 1) or (1, 1, -2, 0) plane, a MOS or MIS interface with a reduced interface state density is formed.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a cross section of an oxidation apparatus.
FIG. 2 shows the oxide film thickness obtained when N-type 4H—SiC (0, 0, 0, 1) and N-type 4H—SiC (0, 0, 0, −1) were oxidized in oxygen. It is a figure which shows pressure dependence.
FIG. 3 shows the pressure dependence of the oxidation rate when 4H—SiC (0, 0, 0, 1) and 4H—SiC (0, 0, 0, −1) are oxidized in a mixed gas atmosphere of ozone and oxygen. It is a figure which shows sex.
Estimated and [4] oxidation rate in 5Torr (0.665kPa), using the relationship that the rate of oxidation pressure is 1/5 to approximately half, the oxidation rate at a lower pressure than 5Torr (0.665kPa) It is a figure which shows the result.
FIG. 5 is a diagram showing an interface state density obtained by measurement using a MOS capacitor manufactured by oxidizing SiC.
FIG. 6 is a diagram showing a cross section of an oxidizer that generates atomic oxygen from ozone by photolysis of ultraviolet rays or the like.
FIG. 7 is a schematic view showing a cross section of a continuous processing apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Oxidizer 2 Ozone generator 3 Shut-off door 4 Exhaust device 5 Pressure control valve 6 Ultraviolet irradiation device 7 Cleaning device 8 Heat treatment device 9 Oxidation furnace 10 Semiconductor substrate 11 Dry oxygen gas 12 Exhaust gas 15 Continuous processing device 16 Conveyance device 17 Load Lock room 18 Load lock door 19 Transfer room

Claims (9)

Forming a source or drain electrode of an insulated gate transistor or an electrode of a semiconductor region of a capacitor having a metal-insulating film-semiconductor region structure on a substrate including a silicon carbide semiconductor region; and cleaning the substrate including the semiconductor region. Forming a gate insulating film of the transistor or a capacitor insulating film of the capacitor on the substrate; forming an electrode on the gate insulating film or the capacitor insulating film; and extracting the electrode Manufacturing a semiconductor device including a step of forming a line,
The step of forming the gate insulating film or the capacitor insulating film is performed in an atmosphere containing atomic oxygen whose substrate temperature is set to 1200 ° C. and which is maintained in a pressure range of 1 Torr (133 Pa) to 10 Torr (1.33 kPa). A method of manufacturing a semiconductor device.   The substrate is a silicon carbide substrate, a gate insulating film having a thickness of 1 nm or more is formed in the step of forming the gate insulating film or the capacitor insulating film, and the atmosphere containing atomic oxygen is 10% by volume or more. The method of manufacturing a semiconductor device according to claim 1, wherein the semiconductor device is generated by decomposition of a source gas containing ozone molecules.   3. The method of manufacturing a semiconductor device according to claim 2, wherein the atmosphere containing atomic oxygen is generated by decomposition of ozone molecules by ultraviolet rays.   After the step of forming the gate insulating film or the capacitor insulating film by oxidation under a pressure of 1 Torr to 10 Torr, a predetermined temperature and a predetermined pressure are set in an atmosphere containing an inert gas. 4. The method for manufacturing a semiconductor device according to claim 1, further comprising a heat treatment step for holding for a long time.   Between the step of forming the gate insulating film or the capacitor insulating film by oxidation under a pressure of 1 Torr to 10 Torr and the step of forming the lead line of the electrode on the gate insulating film or the capacitor insulating film of the transistor, 5. The semiconductor device according to claim 1, further comprising a heat treatment step of holding at a predetermined temperature and a predetermined pressure in a hydrogen-containing atmosphere for a predetermined time. Production method.   The step of cleaning the surface of the silicon carbide semiconductor region, the step of forming the gate insulating film or the capacitor insulating film, and the subsequent heat treatment step are performed continuously in an apparatus shut off from the outside air. A method for manufacturing a semiconductor device according to claim 1.   The method for manufacturing a semiconductor device according to claim 1, wherein the plane orientation of the silicon carbide semiconductor region is a (0, 0, 0, −1) plane.   7. The method of manufacturing a semiconductor device according to claim 1, wherein the plane orientation of the silicon carbide semiconductor region is a (0, 0, 0, 1) plane.   The method for manufacturing a semiconductor device according to claim 1, wherein the plane orientation of the silicon carbide semiconductor region is a (1, 1, −2, 0) plane.

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