A semiconductor device according to one embodiment of the present disclosure includes a low resistance material section and a low thermal resistance material section. The low resistance material section is in contact with a barrier layer, a channel layer, and a source electrode or a drain electrode, and includes a low resistance material having a lower resistance than the channel layer. The low thermal resistance material section is in contact with the channel layer and the buffer layer, and includes a low thermal resistance material having a lower thermal resistance than the channel layer.

A wafer includes a substrate and at least one intermediate layer formed on a surface of the substrate. The at least one intermediate layer covers the surface of the substrate at least partially. An outer surface of the at least one intermediate layer is directed away from the surface of the substrate. The wafer further includes nanostructures grown on the outer surface of the at least one intermediate layer. The at least one intermediate layer is formed in such a way that positions of growth of the nanostructures are predetermined on the outer surface of the at least one intermediate layer. At least one nanostructure material of the nanostructures is assembled at the positions of growth of the nanostructures.

The present invention provides a nitride semiconductor device, including: a silicon substrate; a first lateral transistor over a first region of the silicon substrate and including: a first nitride semiconductor layer formed over the silicon substrate; and a first gate electrode, a first source electrode and a first drain electrode formed over the first nitride semiconductor layer; a second lateral transistor over a second region of the silicon substrate and including: a second nitride semiconductor layer formed over the silicon substrate; and a second gate electrode, a second source electrode and a second drain electrode formed over the second nitride semiconductor layer; a first separation trench formed over a third region; a source/substrate connecting via hole formed over the third region; a first interlayer insulating layer formed over the first source electrode and the second source electrode; and a second interlayer insulating layer formed in the first separation trench.

A nitride semiconductor device includes a nitride semiconductor layer including a first superlattice buffer layer, a second superlattice buffer layer formed above the first superlattice buffer layer, an electron transit layer formed above the second superlattice buffer layer and composed of a first nitride semiconductor, and an electron supply layer formed above the electron transit layer and composed of a second nitride semiconductor. The first superlattice buffer layer has a first superlattice structure including a first layer and a second layer alternately arranged. The first layer is composed of Al.sub.xGa.sub.1xN, where 0<x<1. The second layer is composed of GaN. The second superlattice buffer layer has a second superlattice structure including a third layer and a fourth layer alternately arranged. The third layer is composed of Al.sub.yGa.sub.1yN, where 0<y<x. The fourth layer is composed of GaN.

A method for manufacturing an ohmic contact for a HEMT device, comprising the steps of: forming a photoresist layer, on a semiconductor body comprising a heterostructure; forming, in the photoresist layer, an opening, through which a surface region of the semiconductor body is exposed at said heterostructure; etching the surface region of the semiconductor body using the photoresist layer as etching mask to form a trench in the heterostructure; depositing one or more metal layers in said trench and on the photoresist layer; and carrying out a process of lift-off of the photoresist layer.

According to one embodiment, a semiconductor device includes first, second, and third electrodes, first, second, and third semiconductor layers, and a first insulating member. The first semiconductor layer includes first, second, third, fourth, and fifth partial regions. The third partial region is between the first and second partial regions. The fourth partial region is between the first and third partial regions. The fifth partial region is between the third and second partial regions. The first electrode includes a first electrode portion. The second semiconductor layer includes first and second semiconductor portions. The third semiconductor layer includes first and second semiconductor regions. The second semiconductor region is electrically connected to the first semiconductor region and the first electrode portion. The first insulating member includes a first insulating portion. The first insulating portion is provided between the third partial region and the third electrode.

An HEMT device, comprising: a semiconductor body including a heterojunction structure; a dielectric layer on the semiconductor body; a gate electrode; a drain electrode, facing a first side of the gate electrode; and a source electrode, facing a second side opposite to the first side of the gate electrode; an auxiliary channel layer, which extends over the heterojunction structure between the gate electrode and the drain electrode, in electrical contact with the drain electrode and at a distance from the gate electrode, and forming an additional conductive path for charge carriers that flow between the source electrode and the drain electrode.

A device includes a substrate and insulation regions over a portion of the substrate. A first semiconductor region is between the insulation regions and having a first conduction band. A second semiconductor region is over and adjoining the first semiconductor region, wherein the second semiconductor region includes an upper portion higher than top surfaces of the insulation regions to form a semiconductor fin. The second semiconductor region also includes a wide portion and a narrow portion over the wide portion, wherein the narrow portion is narrower than the wide portion. The semiconductor fin has a tensile strain and has a second conduction band lower than the first conduction band. A third semiconductor region is over and adjoining a top surface and sidewalls of the semiconductor fin, wherein the third semiconductor region has a third conduction band higher than the second conduction band.

A nitride semiconductor device including a substrate, a channel layer, a carbon-poor barrier layer having a recess, a carbon-rich barrier layer disposed over the recess and the carbon-poor barrier layer, and a gate electrode above the recess, wherein the carbon-poor and carbon-rich barrier layers have bandgaps larger than that of the channel layer, the upper surface of the carbon-rich barrier layer includes a first main surface including a source electrode and a drain electrode, and a bottom surface of a depression disposed along the recess, and side surfaces of the depression connecting the first main surface to the bottom surface of the depression, and among edges of the depression of the carbon-rich barrier layer which are boundaries between the first main surface and the side surfaces of the depression, the edge of the depression of the carbon-rich barrier layer closest to the drain electrode is covered with the gate electrode.

A device includes a substrate, insulation regions extending into the substrate, a first semiconductor region between the insulation regions and having a first valence band, and a second semiconductor region over and adjoining the first semiconductor region. The second semiconductor region has a compressive strain and a second valence band higher than the first valence band. The second semiconductor region includes an upper portion higher than top surfaces of the insulation regions to form a semiconductor fin, and a lower portion lower than the top surfaces of the insulation regions. The upper portion and the lower portion are intrinsic. A semiconductor cap adjoins a top surface and sidewalls of the semiconductor fin. The semiconductor cap has a third valence band lower than the second valence band.