A parasitic capacitance and a leak current in a nitride semiconductor device are reduced. For example, a 100 nm-thick buffer layer made of AlN, a 2 μm-thick undoped GaN layer, and 20 nm-thick undoped AlGaN having an Al composition ratio of 20% are epitaxially grown in this order on, for example, a substrate made of silicon, and a source electrode and a drain electrode are formed so as to be in ohmic contact with the undoped AlGaN layer. Further, in the undoped GaN layer and the undoped AlGaN layer immediately below a gate wire, a high resistance region, the resistance of which is increased by, for example, ion implantation with Ar or the like, is formed, and a boundary between the high resistance region and an element region is positioned immediately below the gate wire.

A semiconductor device includes a gate structure extending from a first surface of a semiconductor portion into a mesa section between neighboring field electrode structures and an alignment layer formed on the first surface. The alignment layer includes mask pits formed in the alignment layer in a vertical projection of the field electrode structures. Sidewalls of the mask pits have a smaller tilt angle with respect to the first surface than sidewalls of the field electrode structures. The gate structure is in the vertical projection of a gap between neighboring mask pits.

A normally-off HEMT transistor includes a heterostructure including a channel layer and a barrier layer on the channel layer; a 2DEG layer in the heterostructure; an insulation layer in contact with a first region of the barrier layer; and a gate electrode through the whole thickness of the insulation layer, terminating in contact with a second region of the barrier layer. The barrier layer and the insulation layer have a mismatch of the lattice constant (“lattice mismatch”), which generates a mechanical stress solely in the first region of the barrier layer, giving rise to a first concentration of electrons in a first portion of the two-dimensional conduction channel which is under the first region of the barrier layer which is greater than a second concentration of electrons in a second portion of the two-dimensional conduction channel which is under the second region of the barrier layer.

A lateral double-diffused metal-oxide-semiconductor transistor includes a silicon semiconductor structure and a vertical gate. The vertical gate include a (a) gate conductor extending from a first outer surface of the silicon semiconductor structure into the silicon semiconductor structure and (b) a gate dielectric layer including a least three dielectric sections. Each of the at least three dielectric sections separates the gate conductor from the silicon semiconductor structure by a respective separation distance, where each of the respective separation distances is different from each other of the respective separation distances.

Disclosed herein are quantum dot devices with multiple layers of gate metal, as well as related computing devices and methods. For example, in some embodiments, a quantum dot device may include: a quantum well stack; an insulating material above the quantum well stack, wherein the insulating material includes a trench; and a gate on the insulating material and extending into the trench, wherein the gate includes a first gate metal in the trench and a second gate metal above the first gate metal.

According to one embodiment, a semiconductor device includes a first crystal region, a second crystal region, a third crystal region, and a fourth crystal region. The first crystal region includes magnesium and Al.sub.x1Ga.sub.1-x1N (0≤x1<1). The second crystal region includes Al.sub.x2Ga.sub.1-x2N (0<x2≤1). The third crystal region is provided between the first crystal region and the second crystal region. The third crystal region includes oxygen and Al.sub.x3Ga.sub.1-x3N (0≤x3≤1 and x3<x2). The fourth crystal region is provided between the third crystal region and the second crystal region. The fourth crystal region includes Al.sub.x4Ga.sub.1-x4N (0≤x4<1 and x4<x2).

A power semiconductor device includes a semiconductor layer based on silicon carbide (SiC), a vertical drift region positioned to extend in a vertical direction inside the semiconductor layer and having a first conductive type, a well region positioned in at least one side of the vertical drift region to make contact with the vertical drift region and having a second conductive type, recess gate electrodes extending from a surface of the semiconductor layer into the semiconductor layer and buried in the vertical drift region and the well region to cross the vertical drift region and the well region in a first direction, source regions positioned in the well region between the recess gate electrodes and having the first conductive type, and insulating-layer protective regions surrounding lower portions of the recess gate electrodes, respectively, in the vertical drift region, and having the second conductive type.

A shielded gate MOSFET device and a manufacturing method thereof is provided. In the method, the shielded gate thick dielectric layers are formed with the thick oxide layer process at the bottoms in the trenches, poly is deposited in each trench and is back etched to leave gate poly on the side wall of each trench, whereas the portion, right in the center of each trench, of the thin poly layer is removed to be filled with the contact hole dielectric layer, which achieves the effect of streamlining the process flow.

A device includes a diode that includes a first group III-nitride (III-N) material and a transistor adjacent to the diode, where the transistor includes the first III-N material. The diode includes a second III-N material, a third III-N material between the first III-N material and the second III-N material, a first terminal including a metal in contact with the third III-N material, a second terminal coupled to the first terminal through the first group III-N material. The device further includes a transistor structure, adjacent to the diode structure. The transistor structure includes the first, second, and third III-N materials, a source and drain, a gate electrode and a gate dielectric between the gate electrode and each of the first, second and third III-N materials.

A silicon carbide device includes a stripe-shaped trench gate structure extending from a first surface into a silicon carbide body. The gate structure has a gate length along a lateral first direction. A bottom surface and an active first gate sidewall of the gate structure are connected via a first bottom edge of the gate structure. The silicon carbide device further includes at least one source region of a first conductivity type. A shielding region of a second conductivity type is in contact with the first bottom edge of the gate structure across at least 20% of the gate length.