Provided are a high electron mobility transistor and a method of manufacturing the high electron mobility transistor. The high electron mobility transistor includes a gate electrode provided on a depletion forming layer. The gate electrode includes a first gate electrode configured to form an ohmic contact with the depletion forming layer, and a second gate electrode configured to form a Schottky contact with the depletion forming layer.

A transistor includes a substrate having a first surface and a second surface opposite the first surface, a drift region having a doped region on the first surface of the substrate and a graded doping region on the doped region, a semiconductor fin protruding from the graded doping region and comprising a metal compound layer at an upper portion of the semiconductor fin, a source metal contact on the metal compound layer, a gate layer having a bottom portion directly contacting the graded doping region; and a drain metal contact on the second surface of the substrate.

A method of fabricating a vertical fin-based field effect transistor (FET) includes providing a semiconductor substrate having a first surface and a second surface, the semiconductor substrate having a first conductivity type, epitaxially growing a first semiconductor layer on the first surface of the semiconductor substrate, the first semiconductor layer having the first conductivity type and including a drift layer and a graded doping layer on the drift layer, and epitaxially growing a second semiconductor layer having the first conductivity type on the graded doping layer. The method also includes forming a metal compound layer on the second semiconductor layer, forming a patterned hard mask layer on the metal compound layer, and etching the metal compound layer and the second semiconductor layer using the patterned hard mask layer as a mask exposing a surface of the graded doping layer to form a plurality of fins surrounded by a trench.

An HEMT device of a normally-on type, comprising a heterostructure; a dielectric layer extending over the heterostructure; and a gate electrode extending right through the dielectric layer. The gate electrode is a stack, which includes: a protection layer, which is made of a metal nitride with stuffed grain boundaries and extends over the heterostructure, and a first metal layer, which extends over the protection layer and is completely separated from the heterostructure by said protection layer.

A method of forming an alignment contact includes: providing a III-nitride substrate; epitaxially growing a first III-nitride layer on the III-nitride substrate, wherein the first III-nitride layer is characterized by a first conductivity type; forming a plurality of III-nitride fins on the first III-nitride layer, wherein each the plurality of III-nitride fins is separated by one of a plurality of first recess regions, wherein the plurality of III-nitride fins are characterized by the first conductivity type; epitaxially regrowing a III-nitride source contact portion on each of the plurality of III-nitride fins; and forming a source contact structure on the III-nitride source contact portions.

To provide a nitride semiconductor device excellent in switching characteristics. A nitride semiconductor device includes: a gallium nitride layer having a first principal surface and a second principal surface located on an opposite side to the first principal surface and having a trench formed from the first principal surface to the second principal surface side; and a field effect transistor formed in the gallium nitride layer, wherein the trench has a first side surface and a second side surface inside the trench, the first side surface is a nitrogen face in the surface layer of which nitrogen atoms are located, the second side surface is a gallium face in the surface layer of which gallium atoms are located, and the field effect transistor has: a gate insulating film formed on the first side surface; and a gate electrode formed in the trench and covering the gate insulating film.

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 nitride semiconductor device includes: an electron transit layer composed of a nitride semiconductor; an electron supply layer formed on the electron transit layer and composed of a nitride semiconductor having a bandgap larger than that of the electron transit layer; a gate layer formed on a portion of the electron supply layer and composed of a nitride semiconductor containing acceptor-type impurities; a gate electrode formed on the gate layer; a passivation layer having first and second openings; a source electrode in contact with the electron supply layer via the first opening; and a drain electrode in contact with the electron supply layer via the second opening, wherein the gate layer is located between the first opening and the second opening, and wherein the gate layer includes a first gate layer of Ga-polar GaN and a second gate layer of N-polar GaN formed on the first gate layer.

An electronic device can include a gate structure. In an embodiment, the gate structure can include a gate electrode including a doped semiconductor material, a metal-containing member, a pair of conductive sidewall spacers. The first metal-containing member can overlie the gate electrode. The conductive sidewall spacers can overlie the gate electrode and along opposite sides of the first metal-containing member. In another embodiment, the gate structure can include a gate electrode, a first metal-containing member overlying the gate electrode, and a second metal-containing member overlying the first metal-containing member. The first metal-containing member can have a length that is greater than the length of the second metal-containing member and substantially the same length as the gate electrode.

An HEMT includes a first III-V compound layer. A second III-V compound layer is disposed on the first III-V compound layer. The composition of the first III-V compound layer is different from that of the second III-V compound layer. A gate is disposed on the second III-V compound layer. The gate includes a first P-type III-V compound layer, an undoped III-V compound layer and an N-type III-V compound layer are deposited from bottom to top. The first P-type III-V compound layer, the undoped III-V compound layer, the N-type III-V compound layer and the first III-V compound layer are chemical compounds formed by the same group III element and the same group V element. A drain electrode is disposed at one side of the gate. A drain electrode is disposed at another side of the gate. A gate electrode is disposed directly on the gate.