A semiconductor device includes a support substrate having a first surface capable of supporting the epitaxial growth of at least one III-V semiconductor and a second surface opposing the first surface, at least one mesa positioned on the first surface, each mesa including an epitaxial III-V semiconductor-based multi-layer structure on the first surface of the support substrate, the III-V semiconductor-based multi-layer structure forming a boundary with the first surface and a parasitic channel suppression region positioned laterally adjacent the boundary.

A method of fabricating a semiconductor device includes providing a substrate having a layered fin structure thereon. The layered fin structure includes base fin portion, a sacrificial portion provided on the base fin portion and a channel portion provided on the sacrificial portion. A doping source film is provided on the substrate over the layered fin structure, and diffusing doping materials from the doping source film into a portion of the layered fin structure other than the channel portion to form a diffusion doped region in the layered fin structure. An isolation material is provided on the substrate over at least the diffusion doped region of the layered fin structure.

A disclosed compound semiconductor device includes a channel layer configured to generate carriers; a spacer layer of Al.sub.y1Ga.sub.1-y1N (0.20<y10.70) formed on the channel layer; and a barrier layer of In.sub.x2Al.sub.y2 Ga.sub.1-x2-y2N (0x20.15 and 0.20y2<0.70) formed on the spacer layer, where y1 and y2 satisfy a relationship of y1>y2.

A process of forming a field transistor (FET) and a FET are disclosed. The FET includes a nitride semiconductor stack on a substrate. A pair of n.sup.+-regions made of oxide semiconductor material are provided within respective recesses in the semiconductor stack. Protecting layers, each made of oxide material, cover peripheries of the n.sup.+-regions. Electrodes are provided in openings in the protecting layers to be in direct contact with the n.sup.+-regions.

In some examples, a transistor comprises a gallium nitride (GaN) layer; a GaN-based alloy layer having a top side and disposed on the GaN layer, wherein source, drain, and gate contact structures are supported by the GaN layer; and a first doped region positioned in a drain access region and extending from the top side into the GaN layer.

Semiconductor structures that inhibit the conductivity of parasitic channels are described. In one example, a semiconductor structure includes a substrate, a III-nitride material region over a top surface of the substrate, a first species implanted within at least one region of surface region of the substrate in a first pattern spatially defined across a lateral dimension of the substrate, and a second species implanted within at least one region of the III-nitride material region. The second species can be implanted in a second pattern spatially defined across the lateral dimension of the substrate. The surface region of the substrate includes a parasitic channel. The at least one region of the substrate in which the first species is implanted includes a low-conductivity parasitic channel or is free of the parasitic channel.

A compound semiconductor device includes a substrate, a compound semiconductor layer formed over the substrate, a channel layer formed over the compound semiconductor layer, an electron supply layer formed over the channel layer, and a source electrode, a drain electrode, and a gate electrode that are formed apart from each other over the electron supply layer. A quantum well structure is formed by the compound semiconductor layer, the channel layer, and the electron supply layer.

A high electron mobility transistor (HEMT) device and a manufacturing method thereof are provided. The HEMT device includes a channel layer, a barrier layer, a first gate electrode, a first drain electrode and a first source electrode. The channel layer is disposed on a substrate. A surface of a portion of the channel layer within a first region of the HEMT device includes a polar plane and a non-polar plane. The barrier layer is conformally disposed on the channel layer. The first gate electrode is disposed on the barrier layer, and located within the first region. The first drain electrode and the first source electrode are disposed within the first region, and located at opposite sides of the first gate electrode.

III-nitride materials are generally described herein, including material structures comprising III-nitride material regions and silicon-containing substrates. Certain embodiments are related to gallium nitride materials and material structures comprising gallium nitride material regions and silicon-containing substrates.

A semiconductor device includes a source, a drain, and a channel electrically connected to the source and the drain. The channel has a channel length from the drain to the source which is less than or equal to an electron mean free path of the channel material. A first gate has two arms, each extending between the drain and the source (i.e., at least a portion of the distance between the source and the drain). Each arm of the first gate is disposed proximate to a corresponding first and second edge of the channel. Each arm of the first gate has a periodic profile along an inner boundary, wherein the periodic profiles of each arm are offset from each other such that a distance between the arms is constant. A Bloch voltage applied to the first gate will reduce the effective channel with such that Bloch resonance conditions are met.