Abstract: A method for manufacturing a semiconductor device includes: preparing a processed wafer having a gallium nitride (GaN) wafer and an epitaxial layer on the GaN wafer; forming a device constituent part in a portion of the processes wafer adjacent to a front surface provided by the epitaxial layer; forming a modified layer inside of the processed wafer by applying a laser beam from a back surface side opposite to the front surface side: and dividing the processed wafer at the modified layer. The processed wafer prepared includes a reflective layer for reflecting the laser beam at a position separated from a planned formation position, where the modified layer is to be formed, by a predetermined distance toward the front surface side. The reflective layer contains a layer having a refractive index different from that of a GaN single crystal of an epitaxial layer.

Abstract: A method of manufacturing a semiconductor device includes a trench forming step, a laser irradiation step and a peeling step. In the trench forming step, a trench is formed on a first main surface of a semiconductor substrate having a device structure formed thereon. In the laser irradiation step, a laser is irradiated from a second main surface of the semiconductor substrate to a plane surface that is positioned and extends at a predetermined depth of the semiconductor substrate. In the peeling step, a device layer is peeled off from the semiconductor substrate along the plane surface on which the laser is irradiated. The peeling step may be performed in a state in which the trenches are either unfilled or filled with a material having a lower coefficient of thermal expansion than the semiconductor substrate.

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: In a semiconductor device having a heterojunction type superjunction structure, a drain portion and a source portion are electrically connected to one of a two-dimensional electron gas layer and a two-dimensional hole gas layer, and a gate portion is prevented by an insulating region from directly contacting the one of the two-dimensional election gas layer and the two-dimensional hole gas layer.

Abstract: In a semiconductor device having a heterojunction type superjunction structure, a drain portion and a source portion are electrically connected to one of a two-dimensional electron gas layer and a two-dimensional hole gas layer, and a gate portion is prevented by an insulating region from directly contacting the one of the two-dimensional election gas layer and the two-dimensional hole gas layer.

Abstract: A semiconductor device is capable of accurately sensing a temperature of a semiconductor element incorporated in a semiconductor substrate. The semiconductor device includes a temperature sensor. The temperature sensor includes a first nitride semiconductor layer of p-type, a first sense electrode, and a second sense electrode. The first sense electrode and the second sense electrode are located to be capable of passing an electric current between the first sense electrode and the second sense electrode through the first nitride semiconductor layer.

Abstract: A nitride semiconductor device includes a conductive substrate and a nitride semiconductor layer. The nitride semiconductor layer is disposed on the conductive substrate. The nitride semiconductor layer includes a first transistor structure of a lateral type and a second transistor structure of a lateral type. The conductive substrate includes a first potential control region and a second potential control region capable of controlling potential independently from the first potential control region. In planar view of the nitride semiconductor layer, the first transistor structure overlaps the first potential control region and the second transistor structure overlaps the second potential control region.

Abstract: A nitride semiconductor device includes a conductive substrate and a nitride semiconductor layer. The nitride semiconductor layer is disposed on the conductive substrate. The nitride semiconductor layer includes a first transistor structure of a lateral type and a second transistor structure of a lateral type. The conductive substrate includes a first potential control region and a second potential control region capable of controlling potential independently from the first potential control region. In planar view of the nitride semiconductor layer, the first transistor structure overlaps the first potential control region and the second transistor structure overlaps the second potential control region.

Abstract: A semiconductor device is capable of accurately sensing a temperature of a semiconductor element incorporated in a semiconductor substrate. The semiconductor device includes a temperature sensor. The temperature sensor includes a first nitride semiconductor layer of p-type, a first sense electrode, and a second sense electrode. The first sense electrode and the second sense electrode are located to be capable of passing an electric current between the first sense electrode and the second sense electrode through the first nitride semiconductor layer.