A method of manufacturing a silicon carbide semiconductor device is provided. The method suppresses the increase in the number of manufacturing steps and is capable of suppressing the degradation of ohmic characteristics of an alloy layer with respect to a semiconductor substrate. The method includes a step of forming a metal layer made of a first metal on a semiconductor substrate made of silicon carbide; a step of forming a metal nitride film obtained by nitriding a second metal on the metal layer; a step of directing a laser light through the metal nitride film to form a layer of an alloy of silicon carbide in the semiconductor substrate and the first metal in the metal layer; and a step of forming an electrode on the metal nitride film.

A semiconductor device includes a first semiconductor layer formed on a substrate; a second semiconductor layer and a third semiconductor layer formed on the first semiconductor layer; a fourth semiconductor layer formed on the third semiconductor layer; a gate electrode formed on the fourth semiconductor layer; and a source electrode and a drain electrode formed in contact with the second semiconductor layer. The third semiconductor layer and the fourth semiconductor layer are formed in an area immediately below the gate electrode, the fourth semiconductor layer is formed with a p-type semiconductor material, and the second semiconductor layer and the third semiconductor layer are formed with AlGaN, and the third semiconductor layer has a lower composition ratio of Al than that of the second semiconductor layer.

Generally discussed herein are techniques for and systems and apparatuses configured to control phonons using an electric field. In one or more embodiments, an apparatus can include electrical contacts, two quantum dots embedded in a semiconductor such that when an electrical bias is applied to the electrical contacts, the electric field produced by the electrical bias is substantially parallel to an axis through the two quantum dots, and a phononic wave guide coupled to the semiconductor, the phononic wave guide configured to transport phonons therethrough.

High-voltage, gallium-nitride HEMTs are described that are capable of withstanding reverse-bias voltages of at least 900 V and, in some cases, in excess of 2000 V with low reverse-bias leakage current. A HEMT may comprise a lateral geometry having a gate, a thin insulating layer formed beneath the gate, a gate-connected field plate, and a source-connected field plate.

An embodiment of a semiconductor device includes a semiconductor substrate that includes an upper surface and a channel, a gate electrode disposed over the substrate electrically coupled to the channel, and a Schottky metal layer disposed over the substrate adjacent the gate electrode. The Schottky metal layer includes a Schottky contact electrically coupled to the channel which provides a Schottky junction and at least one alignment mark disposed over the semiconductor substrate. A method for fabricating the semiconductor device includes creating an isolation region that defines an active region along an upper surface of a semiconductor substrate, forming a gate electrode over the semiconductor substrate in the active region, and forming a Schottky metal layer over the semiconductor substrate. Forming the Schottky metal layer includes forming at least one Schottky contact electrically coupled to the channel and providing a Schottky junction, and forming an alignment mark in the isolation region.

A semiconductor device includes: an electron transit layer constituted of GaN; an electron supply layer constituted of In.sub.x1Al.sub.y1Ga.sub.1x1y1N (0x1<1, 0y1<1, 0<1x1y1<1) and provided on the electron transit layer; a source electrode and a drain electrode that are provided on the electron supply layer and located apart from each other; a threshold voltage adjustment layer constituted of In.sub.x2Al.sub.y2Ga.sub.1x2y2N (0x2<1, 0y2<1, 0<1x2y21) of a p-type and provided on a part of the electron supply layer located between the source electrode and the drain electrode; and a gate electrode provided on the threshold voltage adjustment layer. A high resistance layer is respectively interposed both between the gate electrode and the threshold voltage adjustment layer, and between the threshold voltage adjustment layer and the electron supply layer.

A semiconductor device includes a transistor, a semiconductor layer, an active region and a conductive layer. The active region is in the semiconductor layer. The conductive layer is configured to maintain a channel in the active region when the transistor is triggered to be conducted.

A semiconductor device includes a transistor, a semiconductor layer, an active region and a conductive layer. The active region is in the semiconductor layer. The conductive layer is configured to maintain a channel in the active region when the transistor is triggered to be conducted.

The present disclosure generally relates to a semiconductor device that includes a gate electrical contact that forms junctions with different energy barrier heights to a gate layer. In an example, a semiconductor device includes a semiconductor substrate, a drain electrical contact, a source electrical contact, a barrier layer, a gate layer, and a gate electrical contact. The drain and source electrical contacts are on the semiconductor substrate. The barrier layer is over a channel region of the semiconductor substrate between the drain and source electrical contacts. The gate layer is over the barrier layer. The gate layer includes first and second semiconductor portions. The gate electrical contact contacts the gate layer. The gate electrical contact includes first and second metal portions. The first and second metal portions form first and second junctions with the first and second semiconductor portions, respectively. The first and second junctions have different energy barrier heights.

A semiconductor device includes a first semiconductor layer formed on a substrate; a second semiconductor layer and a third semiconductor layer formed on the first semiconductor layer; a fourth semiconductor layer formed on the third semiconductor layer; a gate electrode formed on the fourth semiconductor layer; and a source electrode and a drain electrode formed in contact with the second semiconductor layer. The third semiconductor layer and the fourth semiconductor layer are formed in an area immediately below the gate electrode, the fourth semiconductor layer is formed with a p-type semiconductor material, and the second semiconductor layer and the third semiconductor layer are formed with AlGaN, and the third semiconductor layer has a lower composition ratio of Al than that of the second semiconductor layer.