A method of manufacturing an electrode structure for a device, such as a GaN or AlGaN device is described. In one example, the method includes providing a substrate (212) of GaN or AlGaN with a surface region of the GaN or AlGaN exposed through an opening (216) in a layer of silicon nitride (214) formed on the substrate. The method further includes depositing layers of W (222), in one example, or Ni (220) and W (222), in another example, on the substrate and the layer of silicon nitride using reactive evaporation and photoresist layers (230) having an undercut profile for liftoff. The method further includes removing the photoresist layers having the undercut profile, and depositing layers of WN (224) and Al over the underlying layers of W or Ni and W by sputtering.

Embodiments disclosed herein comprise a high electron mobility transistor (HEMT). In an embodiment, the HEMT comprises a heterojunction channel that includes a first semiconductor layer and a second semiconductor layer over the first semiconductor layer. In an embodiment a first interface layer is between the first semiconductor layer and the second semiconductor layer, and a second interface layer is over the first interface layer. In an embodiment, the HEMT further comprises a source contact, a drain contact, and a gate contact between the source contact and the drain contact.

The present disclosure provides a semiconductor device and a fabrication method thereof. The semiconductor device includes a substrate, a barrier layer disposed above the substrate, and a dielectric layer disposed on the barrier layer and defining a first recess. The semiconductor device further includes a spacer disposed within the first recess and a gate disposed between a first portion of the spacer and a second portion of the spacer, wherein the gate defining a first recess.

A semiconductor device and a process of forming the semiconductor device are disclosed. The semiconductor device type of a high electron mobility transistor (HEMT) has double SiN films on a semiconductor layer, where the first SiN film is formed by the lower pressure chemical vapor deposition (LPCVD) technique, while, the second SiN film is deposited by the plasma assisted CVD (p-CVD) technique. Moreover, the gate electrode has an arrangement of double metals, one of which contains nickel (Ni) as a Schottky metal, while the other is free from Ni and covers the former metal. A feature of the invention is that the first metal is in contact with the semiconductor layer but apart from the second SiN film.

A method of fabricating transistors with short gate length by two-step photolithography is provided. This method utilizes the two-step photolithography by a stepper as well as controlling a first exposed position and a second exposed position to change the gate length.

An integrated circuit device includes an engineered substrate including a substantially single crystal layer and a buffer layer coupled to the substantially single crystal layer. The integrated circuit device also includes a plurality of semiconductor devices coupled to the buffer layer. The plurality of semiconductor devices can include a first power device coupled to a first portion of the buffer layer and a second power device coupled to a second portion of the buffer layer. The first power device includes a first channel region comprising a first end, a second end, and a first central portion disposed between the first end and the second end. The second power device includes a second channel region comprising a third end, a fourth end, and a second central portion disposed between the third end and the fourth end.

In an embodiment, a Group III nitride device includes a multilayer Group III nitride structure and a first ohmic contact arranged on and forming an ohmic contact to the multilayer Group III nitride device structure. The first ohmic contact includes a base portion having a conductive surface, the conductive surface including a peripheral portion and a central portion, the peripheral portion and the central portion being substantially coplanar and being of differing composition, a conductive via positioned on the central portion of the conductive surface and a contact pad positioned on the conductive via.

A Group III-V semiconductor structure having a semiconductor device. The semiconductor device has a source and drain recess regions extending through a barrier layer and into a channel layer. A regrown, doped Group III-V ohmic contact layer is disposed on and in direct contact with the source and drain recess regions. A gate electrode is disposed in a gap in the regrown, doped Group III-V ohmic contact layer and on the barrier layer A dielectric structure is disposed over the ohmic contact layer and over the barrier layer and extending continuously from a region over the source recess region to one side of the stem to portion and then extending continuously from an opposite side of the stem portion to a region over the drain recess region, a portion of the dielectric structure being in contact with the stem portion and the barrier layer.

The present disclosure provides a semiconductor device and a fabrication method thereof. The semiconductor device includes a substrate, a channel layer disposed on the substrate, and a barrier layer disposed on the channel layer. The semiconductor device further includes a dielectric layer disposed on the barrier layer and defining a first recess exposing a portion of the barrier layer. The semiconductor device further includes a first spacer disposed within the first recess, wherein the first spacer comprises a surface laterally connecting the dielectric layer to the barrier layer.

A high electron mobility transistor device including a channel layer, a first barrier layer, a gate structure, and a spacer is provided. The first barrier layer is disposed on the channel layer. The gate structure is disposed on the first barrier layer. The gate structure includes a first P-type gallium nitride layer, a second barrier layer, and a second P-type gallium nitride layer. The first P-type gallium nitride layer is disposed on the first barrier layer. The second barrier layer is disposed on the first P-type gallium nitride layer. The second P-type gallium nitride layer is disposed on the second barrier layer. A width of the second P-type gallium nitride layer is smaller than a width of the first P-type gallium nitride layer. The spacer is disposed on a sidewall of the second P-type gallium nitride layer.