Abstract: A semiconductor device has a semiconductor layer and a substrate. The semiconductor layer constitutes at least a part of a current path, and is made of silicon carbide. The substrate has a first surface supporting the semiconductor layer, and a second surface opposite to the first surface. Further, the substrate is made of silicon carbide having a 4H type single-crystal structure. Further, the substrate has a physical property in which a ratio of a peak strength in a wavelength of around 500 nm to a peak strength in a wavelength of around 390 nm is 0.1 or smaller in photoluminescence measurement. In this way, the semiconductor device is obtained to have a low on-resistance.

Abstract: A semiconductor device has a semiconductor layer and a substrate. The semiconductor layer constitutes at least a part of a current path, and is made of silicon carbide. The substrate has a first surface supporting the semiconductor layer, and a second surface opposite to the first surface. Further, the substrate is made of silicon carbide having a 4H type single-crystal structure. Further, the substrate has a physical property in which a ratio of a peak strength in a wavelength of around 500 nm to a peak strength in a wavelength of around 390 nm is 0.1 or smaller in photoluminescence measurement. In this way, the semiconductor device is obtained to have a low on-resistance.

Abstract: A semiconductor device has a semiconductor layer and a substrate. The semiconductor layer constitutes at least a part of a current path, and is made of silicon carbide. The substrate has a first surface supporting the semiconductor layer, and a second surface opposite to the first surface. Further, the substrate is made of silicon carbide having a 4H type single-crystal structure. Further, the substrate has a physical property in which a ratio of a peak strength in a wavelength of around 500 nm to a peak strength in a wavelength of around 390 nm is 0.1 or smaller in photoluminescence measurement. In this way, the semiconductor device is obtained to have a low on-resistance.

Abstract: A recess is formed by partially etching a silicon carbide substrate. A mask layer is formed on the silicon carbide substrate by means of photolithography using the recess as an alignment mark. An impurity is implanted into the silicon carbide substrate using the mask layer. The silicon carbide substrate is annealed. After the annealing, a first electrode layer is deposited on the silicon carbide substrate. The first electrode layer is patterned by means of photolithography using the recess in the silicon carbide substrate as an alignment mark.

Abstract: A recess is formed by partially etching a silicon carbide substrate. A mask layer is formed on the silicon carbide substrate by means of photolithography using the recess as an alignment mark. An impurity is implanted into the silicon carbide substrate using the mask layer. The silicon carbide substrate is annealed. After the annealing, a first electrode layer is deposited on the silicon carbide substrate. The first electrode layer is patterned by means of photolithography using the recess in the silicon carbide substrate as an alignment mark.

Abstract: A silicon carbide substrate having a main face is prepared. By applying thermal oxidation to the main face of the silicon carbide substrate at a first temperature, an oxide film is formed on the main face. After the oxide film is formed, heat treatment is applied to the silicon carbide substrate at a second temperature higher than the first temperature. An opening exposing a portion of the main face is formed at the oxide film. A Schottky electrode is formed on the main face exposed by the opening.

Abstract: A method for manufacturing a Schottky barrier diode includes the following steps. First, a GaN substrate is prepared. A GaN layer is formed on the GaN substrate. A Schottky electrode including a first layer made of Ni or Ni alloy and in contact with the GaN layer is formed. The step of forming the Schottky electrode includes a step of forming a metal layer to serve as the Schottky electrode and a step of heat treating the metal layer. A region of the GaN layer in contact with the Schottky electrode has a dislocation density of 1×108 cm?2 or less.

Abstract: A semiconductor device includes a semiconductor layer (1) containing GaN and an electrode. The electrode includes an electrode main body (6), a connection-use electrode (8) containing Al and formed at a position farther from the semiconductor layer (1) than the electrode main body (6), and a barrier layer (7) formed between the electrode main body (6) and the connection-use electrode (8), the barrier layer (7) containing at least one selected from the group consisting of W, TiW, WN, TiN, Ta, and TaN. A surface roughness RMS of the barrier layer (7) is 3.0 nm or less.

Abstract: A method of cleaning a SiC semiconductor includes the steps of forming an oxide film at the surface of a SiC semiconductor, and removing the oxide film. At the step of forming an oxide film, an oxide film is formed using ozone water having a concentration greater than or equal to 30 ppm. The forming step preferably includes the step of heating at least one of the surface of the SiC semiconductor and the ozone water. Thus, there can be obtained a method of cleaning a SiC semiconductor that can exhibit cleaning effect on the SiC semiconductor.

Abstract: A first circular surface (11) is provided with a first notch portion (N1a) having a first shape. A second circular surface (21) is opposite to the first circular surface and is provided with a second notch portion (N2a) having a second shape. A side surface (31) connects the first circular surface (11) and the second circular surface (21) to each other. The first notch portion (N1a) and the second notch portion (N2a) are opposite to each other. The side surface (31) has a first depression (Da) connecting the first notch portion (N1a) and the second notch portion (N2a) to each other.

Abstract: A semiconductor device includes a semiconductor layer (1) containing GaN and an electrode. The electrode includes an electrode main body (6), a connection-use electrode (8) containing Al and formed at a position farther from the semiconductor layer (1) than the electrode main body (6), and a barrier layer (7) formed between the electrode main body (6) and the connection-use electrode (8), the barrier layer (7) containing at least one selected from the group consisting of W, TiW, WN, TiN, Ta, and TaN. A surface roughness RMS of the barrier layer (7) is 3.0 nm or less.

Abstract: A semiconductor device includes a semiconductor layer (1) containing GaN and an electrode. The electrode includes an electrode main body (6), a connection-use electrode (8) containing Al and formed at a position farther from the semiconductor layer (1) than the electrode main body (6), and a barrier layer (7) formed between the electrode main body (6) and the connection-use electrode (8), the barrier layer (7) containing at least one selected from the group consisting of W, TiW, WN, TiN, Ta, and TaN. A surface roughness RMS of the barrier layer (7) is 3.0 nm or less.

Abstract: A Schottky barrier diode includes a GaN freestanding substrate having a front surface, a GaN epitaxial layer deposited on the front surface, and an insulation layer deposited on the GaN epitaxial layer at a front surface and having an opening. Furthermore, the Schottky barrier diode also includes an electrode. The electrode is configured by a Schottky electrode provided in the opening in contact with the GaN epitaxial layer, and a field plate electrode connected to the Schottky electrode and also overlapping the insulation layer. The GaN freestanding substrate has a dislocation density of at most 1×108 cm?2.

Abstract: A method for manufacturing a Schottky barrier diode includes the following steps. First, a GaN substrate is prepared. A GaN layer is formed on the GaN substrate. A Schottky electrode including a first layer made of Ni or Ni alloy and in contact with the GaN layer is formed. The step of forming the Schottky electrode includes a step of forming a metal layer to serve as the Schottky electrode and a step of heat treating the metal layer. A region of the GaN layer in contact with the Schottky electrode has a dislocation density of 1×108 cm?2 or less.

Abstract: A method for manufacturing a Schottky barrier diode includes the following steps. First, a GaN substrate is prepared. A GaN layer is formed on the GaN substrate. A Schottky electrode including a first layer made of Ni or Ni alloy and in contact with the GaN layer is formed. The step of forming the Schottky electrode includes a step of forming a metal layer to serve as the Schottky electrode and a step of heat treating the metal layer. A region of the GaN layer in contact with the Schottky electrode has a dislocation density of 1×108 cm?2 or less.

Abstract: A method for manufacturing a SiC semiconductor device includes: a step of forming an oxide film on a surface of a SiC substrate; and a step of removing the oxide film. In the step of forming the oxide film, ozone gas is used. In the step of removing the oxide film, it is preferable to use halogen plasma or hydrogen plasma. In this way, problems associated with a chemical solution can be reduced while obtaining a method and device for manufacturing a SiC semiconductor device, by each of which a cleaning effect can be improved.

Abstract: A semiconductor device has a semiconductor layer and a substrate. The semiconductor layer constitutes at least a part of a current path, and is made of silicon carbide. The substrate has a first surface supporting the semiconductor layer, and a second surface opposite to the first surface. Further, the substrate is made of silicon carbide having a 4H type single-crystal structure. Further, the substrate has a physical property in which a ratio of a peak strength in a wavelength of around 500 nm to a peak strength in a wavelength of around 390 nm is 0.1 or smaller in photoluminescence measurement. In this way, the semiconductor device is obtained to have a low on-resistance.

Abstract: A cleaning method for a SiC semiconductor includes the step of forming an oxide film on a front surface of a SiC semiconductor, and the step of removing the oxide film, and oxygen plasma is used in the step of forming the oxide film. Hydrogen fluoride may be used in the step of removing the oxide film. Thereby, a cleaning effect on the SiC semiconductor can be exhibited.

Abstract: A method of cleaning an SiC semiconductor includes the steps of forming an oxide film on a surface of an SiC semiconductor and removing the oxide film. In the step of removing the oxide film, the oxide film is removed with halogen plasma or hydrogen plasma. In the step of removing the oxide film, fluorine plasma is preferably employed as halogen plasma. The SiC semiconductor can be cleaned such that good surface characteristics are achieved.

Abstract: A method of cleaning a SiC semiconductor includes the steps of forming an oxide film at the surface of a SiC semiconductor, and removing the oxide film. At the step of forming an oxide film, an oxide film is formed using ozone water having a concentration greater than or equal to 30 ppm. The forming step preferably includes the step of heating at least one of the surface of the SiC semiconductor and the ozone water. Thus, there can be obtained a method of cleaning a SiC semiconductor that can exhibit cleaning effect on the SiC semiconductor.