Abstract: A silicon carbide semiconductor device (90), includes: 1) a silicon carbide substrate (1); 2) a gate electrode (7) made of polycrystalline silicon; and 3) an ONO insulating film (9) sandwiched between the silicon carbide substrate (1) and the gate electrode (7) to thereby form a gate structure, the ONO insulating film (9) including the followings formed sequentially from the silicon carbide substrate (1): a) a first oxide silicon film (O) (10), b) an SiN film (N) (11), and c) an SiN thermally-oxidized film (O) (12, 12a, 12b). Nitrogen is included in at least one of the following places: i) in the first oxide silicon film (0) (10) and in a vicinity of the silicon carbide substrate (1), and ii) in an interface between the silicon carbide substrate (1) and the first oxide silicon film (O) (10).

Abstract: A silicon carbide semiconductor device (90), includes: 1) a silicon carbide substrate (1); 2) a gate electrode (7) made of polycrystalline silicon; and 3) an ONO insulating film (9) sandwiched between the silicon carbide substrate (1) and the gate electrode (7) to thereby form a gate structure, the ONO insulating film (9) including the followings formed sequentially from the silicon carbide substrate (1): a) a first oxide silicon film (O) (10), b) an SiN film (N) (11), and c) an SiN thermally-oxidized film (O) (12, 12a, 12b). Nitrogen is included in at least one of the following places: i) in the first oxide silicon film (O) (10) and in a vicinity of the silicon carbide substrate (1), and ii) in an interface between the silicon carbide substrate (1) and the first oxide silicon film (O) (10).

Abstract: A semiconductor device including a semiconductor layer of a first conductivity type; a plurality of body regions of a second conductivity type, each formed in a region extending from the surface of the semiconductor layer to a halfway portion of the same in the thickness direction, and each spaced apart from each other in a direction perpendicular to the thickness direction; source regions of the first conductivity type, each formed on the surface layer part of each body region and spaced away from the edges of each body region; a gate insulating film formed on the semiconductor layer; and gate electrodes formed on the gate insulating film.

Abstract: A semiconductor device includes a first conductive-type semiconductor layer, a second conductive-type body region formed in a surficial portion of the semiconductor layer, a first conductive-type source region formed in a surficial portion of the body region, a gate insulating film provided on the semiconductor layer and containing nitrogen atoms, the gate insulating film including a first portion in contact with the semiconductor layer outside the body region, a second portion in contact with the body region, and a third portion in contact with the source region, and a gate electrode provided on the gate insulating film in an area extending across the semiconductor layer outside the body region, the body region, and the source region. The third portion of the gate insulating film has a thickness greater than the thickness of the first portion and the thickness of the second portion.

Abstract: A silicon carbide semiconductor device (90), includes: 1) a silicon carbide substrate (1); 2) a gate electrode (7) made of polycrystalline silicon; and 3) an ONO insulating film (9) sandwiched between the silicon carbide substrate (1) and the gate electrode (7) to thereby form a gate structure, the ONO insulating film (9) including the followings formed sequentially from the silicon carbide substrate (1): a) a first oxide silicon film (O) (10), b) an SiN film (N) (11), and c) an SiN thermally-oxidized film (O) (12, 12a, 12b). Nitrogen is included in at least one of the following places: i) in the first oxide silicon film (O) (10) and in a vicinity of the silicon carbide substrate (1), and ii) in an interface between the silicon carbide substrate (1) and the first oxide silicon film (O) (10).

Abstract: The semiconductor device according to the present invention includes a semiconductor layer of a first conductivity type, body regions of a second conductivity type plurally formed on a surface layer portion of the semiconductor layer at an interval, a source region of the first conductivity type formed on a surface layer portion of each body region, a gate insulating film provided on the semiconductor layer to extend between the body regions adjacent to each other, a gate electrode provided on the gate insulating film and opposed to the body regions, and a field relaxation portion provided between the body regions adjacent to each other for relaxing an electric field generated in the gate insulating film.

Abstract: A silicon carbide semiconductor device (90), includes: 1) a silicon carbide substrate (1); 2) a gate electrode (7) made of polycrystalline silicon; and 3) an ONO insulating film (9) sandwiched between the silicon carbide substrate (1) and the gate electrode (7) to thereby form a gate structure, the ONO insulating film (9) including the followings formed sequentially from the silicon carbide substrate (1): a) a first oxide silicon film (O) (10), b) an SiN film (N) (11), and c) an SiN thermally-oxidized film (O) (12, 12a, 12b). Nitrogen is included in at least one of the following places: i) in the first oxide silicon film (O) (10) and in a vicinity of the silicon carbide substrate (1), and ii) in an interface between the silicon carbide substrate (1) and the first oxide silicon film (O) (10).

Abstract: A silicon carbide semiconductor device (90), includes: 1) a silicon carbide substrate (1); 2) a gate electrode (7) made of polycrystalline silicon; and 3) an ONO insulating film (9) sandwiched between the silicon carbide substrate (1) and the gate electrode (7) to thereby form a gate structure, the ONO insulating film (9) including the followings formed sequentially from the silicon carbide substrate (1): a) a first oxide silicon film (O) (10), b) an SiN film (N) (11), and c) an SiN thermally-oxidized film (O) (12, 12a, 12b). Nitrogen is included in at least one of the following places: i) in the first oxide silicon film (O) (10) and in a vicinity of the silicon carbide substrate (1), and ii) in an interface between the silicon carbide substrate (1) and the first oxide silicon film (O) (10).

Abstract: A semiconductor device including a semiconductor layer of a first conductivity type; a plurality of body regions of a second conductivity type, each formed in a region extending from the surface of the semiconductor layer to a halfway portion of the same in the thickness direction, and each spaced apart from each other in a direction perpendicular to the thickness direction; source regions of the first conductivity type, each formed on the surface layer part of each body region and spaced away from the edges of each body region; a gate insulating film formed on the semiconductor layer; and gate electrodes formed on the gate insulating film.

Abstract: An AC switch includes a first compound semiconductor MOSFET and a second compound semiconductor MOSFET whose sources are connected with each other, a first output terminal connected to the drain of the first compound semiconductor MOSFET, and a second output terminal connected to the drain of the second compound semiconductor MOSFET. The withstand voltage between the first output terminal and the second output terminal in an off state is not less than 400 V. The resistance between the first output terminal and the second output terminal in an on state is not more than 20 m?.

Abstract: A semiconductor device includes a first conductive type SiC semiconductor substrate; a second conductive type well formed on the SiC semiconductor substrate; a first impurity diffusion layer formed by introducing a first conductive type impurity so as to be partly overlapped with the well in a region surrounding the well; a second impurity diffusion layer formed by introducing the first conductive type impurity in a region spaced apart for a predetermined distance from the impurity diffusion layer in the well; and a gate electrode opposed to a channel region between the first and the second impurity diffusion layers with gate insulating film sandwiched therebetween.

Abstract: A semiconductor device of a double diffused MOS structure employing a silicon carbide semiconductor substrate. The semiconductor device comprises a silicon carbide semiconductor epitaxial layer provided on a surface of the silicon carbide semiconductor substrate and having a first conductivity which is the same conductivity as the silicon carbide semiconductor substrate, and an impurity region formed by doping a surface portion of the silicon carbide semiconductor epitaxial layer with an impurity of a second conductivity, the impurity region having a profile such that a near surface thereof has a relatively low second-conductivity impurity concentration and a deep portion thereof has a relatively high second-conductivity impurity concentration.

Abstract: In a production process for a semiconductor device employing an SiC semiconductor substrate (1), the SiC semiconductor substrate (1) is mounted on a susceptor (23), and a C heating member (3) of carbon is placed on a surface of the SiC semiconductor substrate (1). An annealing process is performed to form an impurity region in the surface of the SiC semiconductor substrate (1) by causing the susceptor (23) and the C heating member (3) to generate heat at high temperatures.

Abstract: A silicon carbide semiconductor device (90), includes: 1) a silicon carbide substrate (1); 2) a gate electrode (7) made of polycrystalline silicon; and 3) an ONO insulating film (9) sandwiched between the silicon carbide substrate (1) and the gate electrode (7) to thereby form a gate structure, the ONO insulating film (9) including the followings formed sequentially from the silicon carbide substrate (1): a) a first oxide silicon film (O) (10), b) an SiN film (N) (11), and c) an SiN thermally-oxidized film (O) (12, 12a, 12b). Nitrogen is included in at least one of the following places: i) in the first oxide silicon film (O) (10) and in a vicinity of the silicon carbide substrate (1), and ii) in an interface between the silicon carbide substrate (1) and the first oxide silicon film (O) (10).

Abstract: A method for producing a semiconductor device (20) is disclosed. The semiconductor device (20) includes: 1) a semiconductor substrate (1, 2), 2) a hetero semiconductor area (3) configured to contact a first main face (1A) of the semiconductor substrate (1, 2) and different from the semiconductor substrate (1, 2) in band gap, 3) a gate electrode (7) contacting, via a gate insulating film (6), a part of a junction part (13) between the hetero semiconductor area (3) and the semiconductor substrate (1, 2), 4) a source electrode (8) configured to connect to the hetero semiconductor area (3), and 5) a drain electrode (9) configured to make an ohmic connection with the semiconductor substrate (1, 2). The method includes the following sequential operations: i) forming the gate insulating film (6); and ii) nitriding the gate insulating film (6).

Abstract: A semiconductor device includes a first conductive type SiC semiconductor substrate; a second conductive type well formed on the SiC semiconductor substrate; a first impurity diffusion layer formed by introducing a first conductive type impurity so as to be partly overlapped with the well in a region surrounding the well; a second impurity diffusion layer formed by introducing the first conductive type impurity in a region spaced apart for a predetermined distance from the impurity diffusion layer in the well; and a gate electrode opposed to a channel region between the first and the second impurity diffusion layers with gate insulating film sandwiched therebetween.

Abstract: In a production process for a semiconductor device employing an SiC semiconductor substrate (1), the SiC semiconductor substrate (1) is mounted on a susceptor (23), and a C heating member (3) of carbon is placed on a surface of the SiC semiconductor substrate (1). An annealing process is performed to form an impurity region in the surface of the SiC semiconductor substrate (1) by causing the susceptor (23) and the C heating member (3) to generate heat at high temperatures.

Abstract: A semiconductor device of a double diffused MOS structure employing a silicon carbide semiconductor substrate. The semiconductor device comprises a silicon carbide semiconductor epitaxial layer provided on a surface of the silicon carbide semiconductor substrate and having a first conductivity which is the same conductivity as the silicon carbide semiconductor substrate, and an impurity region formed by doping a surface portion of the silicon carbide semiconductor epitaxial layer with an impurity of a second conductivity, the impurity region having a profile such that a near surface thereof has a relatively low second-conductivity impurity concentration and a deep portion thereof has a relatively high second-conductivity impurity concentration.