In an embodiment, a Group III nitride-based transistor device is provided that includes a Group III nitride-based body and a p-type Schottky gate including a metal gate on a p-doped Group III nitride structure. The p-doped Group III nitride structure includes an upper p-doped GaN layer in contact with the metal gate and having a thickness d.sub.1, a lower p-doped Group III nitride layer having a thickness d.sub.2 and including p-doped GaN that is arranged on and in contact with the Group III nitride-based body, and at least one p-doped Al.sub.xGa.sub.1-xN layer arranged between the upper p-doped GaN layer and the lower p-doped Group III nitride layer, wherein 0<x<1. The thickness d.sub.2 of the lower p-doped Group III nitride layer is larger than the thickness d.sub.1 of the upper p-doped GaN layer.

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 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.

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 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 semiconductor device includes a buffer layer, a channel layer, a barrier layer, and agate electrode over a substrate, the gate electrode being disposed in a first opening with agate insulating film in between, the first opening running up to the middle of the channel layer through the barrier layer. The concentration of two-dimensional electron gas in a first region on either side of a second opening that will have a channel is controlled to be lower than the concentration of two-dimensional electron gas in a second region between an end of the first region and a source or drain electrode. The concentration of the two-dimensional electron gas in the first region is thus decreased, thereby the conduction band-raising effect of polarization charge is prevented from being reduced. This prevents a decrease in threshold potential, and thus improves normally-off operability.

A high electron mobility transistor (HEMT) includes a first III-V compound layer and a second III-V compound layer disposed on the first III-V compound layer and is different from the first III-V compound layer in composition. A source feature and a drain feature are disposed on the second III-V compound layer. A p-type layer is disposed on a portion of the second III-V compound layer between the source feature and the drain feature. A gate electrode is disposed on the p-type layer. A capping layer is disposed on the second III-V compound layer.

Device architectures based on trapping and de-trapping holes or electrons and/or recombination of both types of carriers are obtained by carrier trapping either in near-interface deep ambipolar states or in quantum wells/dots, either serving as ambipolar traps in semiconductor layers or in gate dielectric/barrier layers. In either case, the potential barrier for trapping is small and retention is provided by carrier confinement in the deep trap states and/or quantum wells/dots. The device architectures are usable as three terminal or two terminal devices.

A semiconductor device includes: an electron transit layer constituted of GaN; an electron supply layer constituted of In.sub.x1Al.sub.y1Ga.sub.1x1y1N (0x1<1, 0y1<1, 0<1x1y1<1) and provided on the electron transit layer; a source electrode and a drain electrode that are provided on the electron supply layer and located apart from each other; a threshold voltage adjustment layer constituted of In.sub.x2Al.sub.y2Ga.sub.1x2y2N (0x2<1, 0y2<1, 0<1x2y21) of a p-type and provided on a part of the electron supply layer located between the source electrode and the drain electrode; and a gate electrode provided on the threshold voltage adjustment layer. A high resistance layer is respectively interposed both between the gate electrode and the threshold voltage adjustment layer, and between the threshold voltage adjustment layer and the electron supply layer.

A uni-terminal transistor device is described. In one embodiment, an n-channel transistor having p-terminal characteristics comprises a first semiconductor layer having a discrete hole level; a second semiconductor layer having a conduction band whose minimum level is lower than that of the first semiconductor layer; a wide bandgap semiconductor barrier layer disposed between the first and the second semiconductor layers; a gate dielectric layer disposed above the first semiconductor layer; and a gate metal layer disposed above the gate dielectric layer and having an effective workfunction selected to position the discrete hole level below the minimum level of the conduction band of the second semiconductor layer for zero bias applied to the gate metal layer and to obtain p-terminal characteristics.

A hybrid transistor circuit is disclosed for use in III-Nitride (III-N) semiconductor devices, comprising a Silicon (Si)-based Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), a Group III-Nitride (III-N)-based Field-Effect Transistor (FET), and a driver unit. A source terminal of the III-N-based FET is connected to a drain terminal of the Si-based MOSFET. The driver unit has at least one input terminal, and two output terminals connected to the gate terminals of the transistors respectively. The hybrid transistor circuit is turned on through the driver unit by switching on the Silicon-based MOSFET first before switching on the III-N-based FET, and is turned off through the driver unit by switching off the III-N-based FET before switching off the Silicon-based MOSFET. Also disclosed are integrated circuit packages and semiconductor structures for forming such hybrid transistor circuits. The resulting hybrid circuit provides power-efficient and robust use of III-Nitride semiconductor devices.