A semiconductor device includes a first semiconductor layer on a substrate, a second semiconductor layer containing an n-type dopant, on the first semiconductor layer, a third semiconductor layer having a resistance greater than a resistance of the second semiconductor layer, on the second semiconductor layer, a fourth semiconductor layer containing a nitride semiconductor, on the third semiconductor layer, and a fifth semiconductor layer containing a nitride semiconductor having a band gap greater than a band gap of the fourth semiconductor layer, on the fourth semiconductor layer.

In an embodiment, a switch circuit includes a bidirectional switch including a first input/output node, a second input/output node, a first diode and a second diode. The first diode and the second diode are coupled anti-serially between the first input/output node and the second input/output node.

Circuits, structures and techniques for independently connecting a surrounding material in a part of a semiconductor device to a contact of its respective device. To achieve this, a combination of one or more conductive wells that are electrically isolated in at least one bias polarity are provided.

A method for forming a high electron mobility transistor (HEMT) device with a plurality of alternating layers of one or more undoped gallium nitride (GaN) layers and one or more carbon doped gallium nitride layers (c-GaN), and an HEMT device formed by the method is disclosed. In one embodiment, the method includes forming a channel layer stack on a substrate, the channel layer stack having a plurality of alternating layers of one or more undoped gallium nitride (GaN) layers and one or more carbon doped gallium nitride layers (c-GaN). The method further includes forming a barrier layer on the channel layer stack. In one embodiment, the channel layer stack is formed by growing each of the one or more undoped gallium nitride (GaN) layers in growth conditions that suppress the incorporation of carbon in gallium nitride, and growing each of the one or more carbon doped gallium nitride (c-GaN) layers in growth conditions that promote the incorporation of carbon in gallium nitride.

Characteristics of a semiconductor device are improved. A semiconductor device includes a potential fixing layer, a channel underlayer, a channel layer, and a barrier layer formed above a substrate, a trench that penetrates the barrier layer and reaches as far as a middle of the channel layer, a gate electrode disposed by way of an insulation film in the trench, and a source electrode and a drain electrode formed respectively over the barrier layer on both sides of the gate electrode. A coupling portion inside the through hole that reaches as far as the potential fixing layer electrically couples the potential fixing layer and the source electrode. This can reduce fluctuation of the characteristics such as a threshold voltage and an on-resistance.

An epitaxial group-ill-nitride buffer-layer structure is provided on a heterosubstrate, wherein the buffer-layer structure has at least one stress-management layer sequence including an interlayer structure arranged between and adjacent to a first and a second group-ill-nitride layer, wherein the interlayer structure comprises a group-ill-nitride interlayer material having a larger band gap than the materials of the first and second group-ill-nitride layers, and wherein a p-type-dopant-concentration profile drops, starting from at least 11018 cm-3, by at least a factor of two in transition from the interlayer structure to the first and second group-ill-nitride layers.

A semiconductor device includes a semiconductor substrate which includes a first surface, a second surface, and an end portion, the semiconductor substrate including a first region of a p-type and a second region of an n-type provided in a corner portion of the semiconductor substrate between the first surface and the end surface, a nitride semiconductor layer on the first surface, and an electrode on the nitride semiconductor layer.

A compound semiconductor device includes: a compound semiconductor region having a surface in which a step is formed; a first electrode formed so as to overlie the upper surface of the step, the upper surface being a non-polar face; and a second electrode formed along a side surface of the step so as to be spaced apart from the first electrode in a vertical direction, the side surface being a polar face.

In one general aspect, a power device can include an active region having a plurality of pillars of a first conductivity type alternately arranged with a plurality of pillars of a second conductivity type. The power device can include a termination region surrounding at least a portion of the active region and can have a plurality of pillars of the first conductivity type alternately arranged with a plurality of pillars of the second conductivity type. Each of the plurality of pillars of the first conductivity type in the active region and the termination region can be defined by a trench. The power device can include an enrichment region at a bottom portion of one of the plurality of pillars of the first conductivity type in the active region.

A silicon substrate having a III-V compound layer disposed thereon is provided. A diode is formed in the silicon substrate through an ion implantation process. The diode is formed proximate to an interface between the silicon substrate and the III-V compound layer. An opening is etched through the III-V compound layer to expose the diode. The opening is filled with a conductive material. Thereby, a via is formed that is coupled to the diode. A High Electron Mobility Transistor (HEMT) device is formed at least partially in the III-V compound layer.