Abstract: In a surface treatment method for a gallium oxide-based semiconductor substrate, a surface of the gallium oxide-based semiconductor substrate is flattened by dry etching with a self-bias of 150 V or more. After the surface of the gallium oxide-based semiconductor substrate is flattened, the surface of the gallium oxide-based semiconductor substrate is washed with a chemical solution containing H2SO4 to expose a step terrace structure on the surface of the gallium oxide-based semiconductor substrate.

Abstract: A method of manufacturing a gate switching device is provided. The method includes: forming an oxide insulating layer on a gallium nitride semiconductor layer of n-type or i-type; forming a gallium oxide layer at an interface between the oxide insulating layer and the gallium nitride semiconductor layer by heating the oxide insulating layer and the gallium nitride semiconductor layer at a temperature higher than a temperature of the oxide insulating layer and the gallium nitride semiconductor layer in the formation of the oxide insulating layer; and forming a gate electrode opposed to the gallium nitride semiconductor layer via the gallium oxide layer.

Abstract: A semiconductor device is provided with an electronic transit layer, an electron supply layer, a source region, a drain electrode, a source electrode and an insulated gate. In a region between the drain electrode and the insulated gate, a two-dimensional electron gas layer is configured to be generated at a hetero junction between the electronic transit layer and the electron supply layer. A part of the insulated gate is configured to face to the source region.

Abstract: A semiconductor device is provided with an electronic transit layer, an electron supply layer, a source region, a drain electrode, a source electrode and an insulated gate. In a region between the drain electrode and the insulated gate, a two-dimensional electron gas layer is configured to be generated at a hetero junction between the electronic transit layer and the electron supply layer. A part of the insulated gate is configured to face to the source region.

Abstract: In a motor device 300 mounted on a mobile body, a pressurizing mechanism for increasing the pressure in a motor chamber 14 in which a motor is installed has a compressor 30, which is driven to rotate by an engine 20 serving as driving means for driving the mobile body, to produce compressed air for motor chamber pressurization, and the compressed air coming from the compressor 30 is fed into the motor chamber 14 through a pipe 72 almost constantly while the engine 20 is being driven.

Abstract: There is provided a motor insulation protecting device 200 comprising a motor 40 installed in a motor chamber 14; an inverter 16 that supplies an inverter voltage for driving the motor 40; and pressurizing means for monitoring an internal pressure in the motor chamber 14 and the inverter voltage of the inverter 16, and increasing the pressure in the motor chamber when an occurrence of discharge of the motor is predicted, wherein the pressurizing means comprises a pressure detection unit 50 that detects the internal pressure in the motor chamber 14; a voltage detection unit that is provided in a control unit 60, and detects the inverter voltage of the inverter 16; and a pressurizing mechanism 70 that increases the pressure in the motor chamber 14 in accordance with the output from the control unit 60 when the detected internal pressure is lower than a preset discharge occurrence prediction internal pressure, and the detected inverter voltage is higher than a preset discharge occurrence prediction inverter volt

Abstract: An inverter for driving a motor includes a plurality of power semiconductor devices. The plurality of power semiconductor devices include a resistance electrically connected between a collector and an emitter of an IGBT element. Each of the power semiconductor devices forms any one of a U-phase arm, a V-phase arm and a W-phase arm of the inverter. As a result, a discharge resistance is built in the inverter, and therefore, it is not required to prepare the discharge resistance separately. Thus, the number of components required for a motor drive apparatus can be decreased and the number of operation steps can be reduced.

Abstract: An inverter for driving a motor includes a plurality of power semiconductor devices. The plurality of power semiconductor devices include a resistance electrically connected between a collector and an emitter of an IGBT element. Each of the power semiconductor devices forms any one of a U-phase arm, a V-phase arm and a W-phase arm of the inverter. As a result, a discharge resistance is built in the inverter, and therefore, it is not required to prepare the discharge resistance separately. Thus, the number of components required for a motor drive apparatus can be decreased and the number of operation steps can be reduced.

Abstract: There is provided a motor insulation protecting device 200 comprising a motor 40 installed in a motor chamber 14; an inverter 16 that supplies an inverter voltage for driving the motor 40; and pressurizing means for monitoring an internal pressure in the motor chamber 14 and the inverter voltage of the inverter 16, and increasing the pressure in the motor chamber when an occurrence of discharge of the motor is predicted, wherein the pressurizing means comprises a pressure detection unit 50 that detects the internal pressure in the motor chamber 14; a voltage detection unit that is provided in a control unit 60, and detects the inverter voltage of the inverter 16; and a pressurizing mechanism 70 that increases the pressure in the motor chamber 14 in accordance with the output from the control unit 60 when the detected internal pressure is lower than a preset discharge occurrence prediction internal pressure, and the detected inverter voltage is higher than a preset discharge occurrence prediction inverter volt

Abstract: In a motor device 300 mounted on a mobile body, a pressurizing mechanism for increasing the pressure in a motor chamber 14 in which a motor is installed has a compressor 30, which is driven to rotate by an engine 20 serving as driving means for driving the mobile body, to produce compressed air for motor chamber pressurization, and the compressed air coming from the compressor 30 is fed into the motor chamber 14 through a pipe 72 almost constantly while the engine 20 is being driven.

Abstract: The present invention provides a p-type group III nitride semiconductor production method which is excellent in terms of reliability and reproducibility. A photoresist mask is formed on a surface of an n?-GaN layer. Subsequently, an Mg film is formed so as to cover the n?-GaN layer and the photoresist mask, and an Ni/Pt metal film is formed on the Mg film. Thereafter, the photoresist mask is removed, whereby the Mg film and the metal film remain only on a portion of the n?-GaN layer where a p-type region is formed. Subsequently, when thermal treatment is performed in an ammonia atmosphere at 900° C. for three hours, Mg is diffused in the n?-GaN layer while being activated. Therefore, a p-type region is formed. Thereafter, the Mg film and the metal film are removed by use of aqua regia.