There are disclosed herein various implementations of a charge trapping prevention III-Nitride transistor. Such a transistor may be a III-Nitride high electron mobility transistor (HEMT) including a III-Nitride intermediate body situated over a substrate, a channel layer situated over the III-Nitride intermediate body, and a barrier layer situated over the channel layer. The channel layer and the barrier layer are configured to produce a two-dimensional electron gas (2DEG). In addition, the III-Nitride transistor includes a dielectric layer situated over the barrier layer, a gate coupled to the barrier layer, and a drain electrode and a source electrode each extending through the dielectric layer. The drain electrode makes ohmic contact with one or both of the barrier layer and a charge trapping prevention layer situated between the dielectric layer and the barrier layer.

A field-effect transistor includes an n-type semiconductor layer that includes a Ga.sub.2O.sub.3-based single crystal and a plurality of trenches opening on one surface, a gate electrode buried in each of the plurality of trenches, a source electrode connected to a mesa-shaped region between adjacent trenches in the n-type semiconductor layer, and a drain electrode directly or indirectly connected to the n-type semiconductor layer on an opposite side to the source electrode.

A memory cell for storing one or more bits of information has a control gate, a source terminal and a drain terminal. A semiconductor substrate is located between the source and drain terminals, and a floating gate is disposed between the control gate and the semiconductor substrate. The floating gate is electrically isolated from the control gate by a charge trapping barrier, and is electrically isolated from the semiconductor substrate by a charge blocking barrier. At least one of the charge trapping barrier and the charge blocking barrier contains a III-V semiconductor material. The charge trapping barrier is adapted to enable the selective passage of charge carriers between the control gate and the floating gate, in use, to modify the one or more bits of information stored by the memory cell.

Apparatus and circuits including transistors with different threshold voltages and methods of fabricating the same are disclosed. In one example, a semiconductor structure is disclosed. The semiconductor structure includes: a substrate; an active layer that is formed over the substrate and comprises a plurality of active portions; a polarization modulation layer comprising a plurality of polarization modulation portions each of which is disposed on a corresponding one of the plurality of active portions; and a plurality of transistors each of which comprises a source region, a drain region, and a gate structure formed on a corresponding one of the plurality of polarization modulation portions. The transistors have at least three different threshold voltages.

A semiconductor device includes: a channel layer which is made of In.sub.pAl.sub.qGa.sub.1-p-qN (0≦p+q≦1, 0≦p, and 0≦q); a barrier layer which is formed on the channel layer and is made of In.sub.rAl.sub.sGa.sub.1-r-sN (0≦r+s≦1, 0≦r) having a bandgap larger than that of the channel layer; a diffusion suppression layer which is selectively formed on the barrier layer and is made of In.sub.tAl.sub.uGa.sub.1-t-uN (0≦t+u≦1, 0≦t, and s>u); a p-type conductive layer which is formed on the diffusion suppression layer and is made of In.sub.xAl.sub.yGa.sub.1-x-yN (0≦x+y≦1, 0≦x, and 0≦y) having p-type conductivity; and a gate electrode which is formed on the p-type conductive layer.

A semiconductor device includes: a first transistor provided with an electron transit layer made of a nitride semiconductor, a first gate electrode, a first source electrode, and a first drain electrode; and a second transistor that includes a second gate electrode, a second source electrode, and a second drain electrode. The first gate electrode and the second drain electrode are electrically connected to each other, while the first source electrode and the second source electrode are not electrically connected to each other.

A semiconductor structure includes a substrate, a buffer layer, a channel layer, a barrier layer, a doped compound semiconductor layer, and a composite blocking layer. The buffer layer is on the substrate. The channel layer is on the buffer layer. The barrier layer is on the channel layer. The doped compound semiconductor layer is on the barrier layer. The composite blocking layer is on the doped compound semiconductor layer, the composite blocking layer and the barrier layer include the same Group III element, and the atomic percent of the same Group III element in the composite blocking layer increases with the distance from the doped compound semiconductor layer.

A semiconductor structure includes a substrate, a channel layer, a barrier layer, a source structure, a drain structure, a doped compound semiconductor layer, a dielectric layer, and a gate structure. The channel layer is disposed on the substrate. The barrier layer is disposed on the channel layer. The source structure and the drain structure are disposed on opposite sides of the barrier layer. The doped compound semiconductor layer is disposed on the barrier layer. The doped compound semiconductor layer has a first side adjacent to the source structure and a second side adjacent to the drain structure. The doped compound semiconductor layer has at least one opening exposing at least a portion of the barrier layer. The dielectric layer is disposed on the doped compound semiconductor layer and the barrier layer. The gate structure is disposed on the doped compound semiconductor layer.

A high electron mobility transistor (HEMT) made of nitride semiconductor materials, and a method to form the HEMT are disclosed. The HEMT includes a channel layer made of GaN, a barrier layer made of one of AlGaN, InAlN, and InAlGaN on the GaN channel layer, a cap layer made of n-type GaN on the barrier layer, and an insulating layer on the cap layer. The insulating layer has an opening into which the gate is formed. The cap layer has a region in the opening that has a thickness smaller than a thickness of portions of the cap layer that are outside of such region. The outside portions have a thickness that is preferably 5 nm at most.

This normally-off mode polarization super junction GaN-based FET has an undoped GaN layer 11, an Al.sub.xGa.sub.1-xN layer 12, an island-like undoped GaN layer 13, a p-type GaN layer 14 and a p-type In.sub.yGa.sub.1-yN layer 15 which are stacked in order. The FET has a gate electrode 16 on the uppermost layer, a source electrode 17 and a drain electrode 17 on the Al.sub.xGa.sub.1-xN layer 12 and a p-type In.sub.zGa.sub.1-zN layer 19 and a gate electrode 20 which are located beside one end of the undoped GaN layer 13 on the Al.sub.xGa.sub.1-xN layer 12. The gate electrode 20 may be provided on the p-type In.sub.zGa.sub.1-zN layer 19 via a gate insulating film. At a non-operating time, n.sub.0≤n.sub.1<n.sub.2<n.sub.3 is satisfied for the concentration n.sub.0 of the 2DEG 22 formed in the undoped GaN layer 11/the Al.sub.xGa.sub.1-xN layer 12 hetero-interface just below the gate electrode 20, the concentration n.sub.1 of the 2DEG 22 just below the gate electrode 16, the concentration n.sub.2 of the 2DEG 22 in the polarization super junction region and the concentration n.sub.3 of the 2DEG 22 in the part between the polarization super junction region and the drain electrode 18.