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.

A method of forming a semiconductor structure in which a III-V compound semiconductor channel fin portion is formed on a dielectric material is provided. The method includes forming a III-V material stack on a surface of a bulk semiconductor substrate. Patterning of the III-V material stack is then employed to provide a pre-fin structure that is located between, and in contact with, pre-pad structures. The pre-pad structures are used as an anchoring agent when a III-V compound semiconductor channel layer portion of the III-V material stack and of the pre-fin structure is suspended by removing a topmost III-V compound semiconductor buffer layer portion of the material stack from the pre-fin structure. A dielectric material is then formed within the gap provided by the suspending step and thereafter a fin cut process is employed.

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.

Techniques for forming closely packed hybrid nanowires are provided. In one aspect, a method for forming hybrid nanowires includes: forming alternating layers of a first and a second material in a stack on a substrate; forming a first trench(es) and a second trench(es) in the stack; laterally etching the layer of the second material selectively within the first trench(es) to form first cavities in the layer; growing a first epitaxial material within the first trench(es) filling the first cavities; laterally etching the layer of the second material selectively within the second trench(es) to form second cavities in the layer; growing a second epitaxial material within the second trench(es) filling the second cavities, wherein the first epitaxial material in the first cavities and the second epitaxial material in the second cavities are the hybrid nanowires. A nanowire FET device and method for formation thereof are also provided.

Techniques for forming closely packed hybrid nanowires are provided. In one aspect, a method for forming hybrid nanowires includes: forming alternating layers of a first and a second material in a stack on a substrate; forming a first trench(es) and a second trench(es) in the stack; laterally etching the layer of the second material selectively within the first trench(es) to form first cavities in the layer; growing a first epitaxial material within the first trench(es) filling the first cavities; laterally etching the layer of the second material selectively within the second trench(es) to form second cavities in the layer; growing a second epitaxial material within the second trench(es) filling the second cavities, wherein the first epitaxial material in the first cavities and the second epitaxial material in the second cavities are the hybrid nanowires. A nanowire FET device and method for formation thereof are also provided.

A semiconductor device including a device channel with a gate-drain region having a carrier concentration that varies laterally along a direction from the gate contact to the drain contact is provided. Lateral variation of the carrier concentration can be implemented by laterally varying one or more attributes of one or more layers located in the gate-drain region of the device.

Provided are a group 13 nitride composite substrate allowing for the production of a semiconductor device suitable for high-frequency applications while including a conductive GaN substrate, and a semiconductor device produced using this substrate. The group 13 nitride composite substrate includes a base material of an n-conductivity type formed of GaN, a base layer located on the base material, being a group 13 nitride layer having a resistivity of 110.sup.6 .Math.cm or more, a channel layer located on the base layer, being a GaN layer having a total impurity density of 110.sup.17/cm.sup.3 or less, and a barrier layer that is located on the channel layer and is formed of a group 13 nitride having a composition Al.sub.xIn.sub.yGa.sub.1-x-yN (0x1, 0y1).

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 current aperture vertical electron transistor (CAVET) with ammonia (NH.sub.3) based molecular beam epitaxy (MBE) grown p-type Gallium Nitride (p-GaN) as a current blocking layer (CBL). Specifically, the CAVET features an active buried Magnesium (Mg) doped GaN layer for current blocking purposes. This structure is very advantageous for high power switching applications and for any device that requires a buried active p-GaN layer for its functionality.

A device includes a source region, a drain region, and a semiconductor channel connecting the source region to the drain region. The semiconductor channel includes a source-side channel portion adjoining the source region, wherein the source-side channel portion has a first bandgap, and a drain-side channel portion adjoining the drain region. The drain-side channel portion has a second bandgap different from the first bandgap.