A method for manufacturing nitride semiconductor device includes a second step of forming, on a gate layer material film, a gate electrode film that is a material film of a gate electrode, a third step of selectively etching the gate electrode film to form the gate electrode 22 of a ridge shape, and a fourth step of selectively etching the gate layer material film to form a semiconductor gate layer 21 of a ridge shape with the gate electrode 22 disposed at a width intermediate portion of a front surface thereof. The third step includes a first etching step for forming a first portion 22A from an upper end to a thickness direction intermediate portion of the gate electrode 22 and a second etching step being a step differing in etching condition from the first etching step and being for forming a remaining second portion 22B of the gate electrode.

A high-electron mobility transistor includes a substrate; a channel layer on the substrate; a AlGaN layer on the channel layer; and a P—GaN gate on the AlGaN layer. The AlGaN layer comprises a first region and a second region. The first region has a composition that is different from that of the second region.

A high electron mobility transistor (HEMT) made of primarily nitride semiconductor materials is disclosed. The HEMT, which is a type of reverse HEMT, includes, on a C-polar surface of a SiC substrate, a barrier layer and a channel layer each having N-polar surfaces in respective top surfaces thereof. The HEMT further includes an intermediate layer highly doped with impurities and a Schottky barrier layer on the channel layer. The Schottky barrier layer and a portion of the intermediate layer are removed in portions beneath non-rectifying electrodes but a gate electrode is provided on the Schottky barrier layer.

A method for manufacturing a semiconductor device includes preparing a first substrate provided with a first pattern on a first surface, and a semiconductor chip having a second surface, and a third surface opposite to the second surface, and including a second pattern provided on the second surface, recognizing the first pattern from a position near the first surface among the first surface and an opposite surface thereof in the first substrate, recognizing the second pattern by transmitting through the semiconductor chip from a position near the third surface among the second surface and the third surface in the semiconductor chip, aligning the semiconductor chip and the first substrate based on a recognition result of the first pattern and the second pattern, and bonding the semiconductor chip to the first substrate so that the second surface faces the first surface.

A layer structure for a normally-off transistor has an electron-supply layer made of a group-III-nitride material, a back-barrier layer made of a group-III-nitride material, a channel layer between the electron-supply layer and the back-barrier layer, made of a group-III-nitride material having a band-gap energy that is lower than the band-gap energies of the other layer mentioned. The material of the back-barrier layer is of p-type conductivity, while the material of the electron-supply layer and the material of the channel layer are not of p-type conductivity, the band-gap energy of the electron-supply layer is smaller than the band-gap energy of the back-barrier layer. In absence of an external voltage a lower conduction-band-edge of the third group-III-nitride material in the channel layer is higher in energy than a Fermi level of the material in the channel layer.

Photonic devices having a quantum well structure that includes a Group III-N material, and a Al.sub.1-xSc.sub.xN cladding layer disposed on the quantum well structure, where 0<x≤0.45, the Al.sub.1-xSc.sub.xN cladding layer having a lower refractive index than the index of refraction of the quantum well structure.

A High Electron Mobility Transistor (HEMT) device can include an AlN buffer layer on a substrate and an epi-GaN channel layer on the AlN buffer layer. An AlN barrier layer can be on the Epi-GaN channel layer to provide a channel region in the epi-GaN channel layer. A GaN drain region can be recessed into the epi-GaN channel layer at a first end of the channel region and a GaN source region can be recessed into the epi-GaN channel layer at a second end of the channel region opposite the first end of the channel region. A gate electrode can include a neck portion with a first width that extends a first distance above the AlN barrier layer between the GaN drain region and the GaN source region to a head portion of the gate electrode having a second width that is greater than the first width.

A Group III-Nitride quantum well laser including a distributed Bragg reflector (DBR). In some embodiments, the DBR includes Scandium. In some embodiments, the DBR includes Al.sub.1-xSc.sub.xN, which may have 0<x≤0.45.

A III-V semiconductor die for die crack detection is provided. The III-V semiconductor die includes a device area. The III-V semiconductor die further includes a doped semiconductor ring region. The doped semiconductor ring region surrounds the device area. At least one active device or at least one passive device is formed in the device area of the III-V semiconductor die.

A method for making a multilayered device on an engineered substrate having a substrate coefficient of thermal expansion includes growing a buffer layer on the engineered substrate, and growing a first epitaxial layer on the buffer layer. The first epitaxial layer is characterized by an epitaxial coefficient of thermal expansion substantially equal to the substrate coefficient of thermal expansion.