A nitride semiconductor device includes a SiC substrate having a hexagonal crystal structure and including a main surface inclined with respect to a c-plane at an off-angle from 2 to 6 in a specific crystal direction, a nitride semiconductor layer located on the main surface of the SiC substrate and including an electron transit layer and an electron supply layer, and a gate electrode, a source electrode, and a drain electrode located on the nitride semiconductor layer. The main surface is parallel to a first direction, a second direction orthogonal to the first direction, and a third direction coinciding with the specific crystal direction in plan view. The source electrode and the drain electrode are separated in the first direction. The gate electrode extends in the second direction between the source electrode and the drain electrode. The first direction intersects the third direction at an angle of 9015.

A semiconductor device and a method for forming the same are provided. The semiconductor device includes a substrate, a buffer layer on the substrate, a channel layer on the buffer layer, a barrier layer on the channel layer and a gate structure on the barrier layer. The gate structure includes a gate layer, a gate electrode layer, a first protection pattern layer and second protection spacers. The gate electrode layer covers the gate layer. The first protection pattern layer covers a first top surface of the gate electrode layer. The second protection spacers cover first side surfaces of the gate electrode layer, second side surfaces of the first protection pattern layer and a portion of the gate layer. First interfaces between the second protection spacers and the gate layer are coplanar with a second interface, which is between the gate electrode layer and the gate layer.

A semiconductor device includes a substrate, a first transistor unit having a first drain electrode, a first gate electrode, and a first source electrode, a second transistor unit having a second source electrode, a second gate electrode, and a second drain electrode, a gate wiring provided between the first source electrode and the second source electrode and electrically connected to the first gate electrode and the second gate electrode, a first cover metal layer electrically connected to the first source electrode, at least an upper portion of the first cover metal layer projecting toward the gate wiring more than the first source electrode, and a second cover metal layer electrically connected to the second source electrode, at least an upper portion of the second cover metal layer projecting toward the gate wiring more than the second source electrode.

A nitride semiconductor device includes: a substrate; a first nitride semiconductor layer provided over the substrate; a second nitride semiconductor layer that is on the first nitride semiconductor layer and includes a band gap larger than a band gap of the first nitride semiconductor layer; and a third nitride semiconductor layer that is on the second nitride semiconductor layer and includes a band gap larger than the band gap of the first nitride semiconductor layer. The second nitride semiconductor layer includes a damaged region in which an n-type impurity is selectively added by ion implantation. A diffusion region in which the n-type impurity is diffused is present in a vicinity of the damaged region. The nitride semiconductor device further includes: an ohmic electrode provided above the damaged region. The ohmic electrode is in ohmic contact with the diffusion region.

A semiconductor device includes a GaN FET on a silicon substrate and a buffer layer of III-N semiconductor material, with a columnar region, a transition region surrounding the columnar region, and an inter-columnar region around the transition region. The columnar region is higher than the inter-columnar region. The GaN FET includes a gate of III-N semiconductor material with a thickness greater than twice the vertical range of the top surface of the buffer layer in the columnar region. A difference between the gate thickness over the columnar region and over the transition region is less than half of the vertical range of the top surface of the buffer layer in the columnar surface. The semiconductor device may be formed by forming a gate layer of III-N semiconductor material over the barrier layer by a gate MOVPE process using a carrier gas that includes zero to 40 percent hydrogen gas.

In an embodiment, a Group III nitride-based transistor device includes a first passivation layer arranged on a first major surface of a Group III nitride-based layer, a second passivation layer arranged on the first passivation layer, a source ohmic contact, a drain ohmic contact and a gate positioned on the first major surface of a Group III nitride-based layer, and a field plate, the field plate being laterally arranged between and spaced apart from the gate and the drain ohmic contact.

A high electron mobility transistor includes a substrate, a semiconductor channel layer, a semiconductor barrier layer, a gate field plate, a source electrode, at least one first field plate, and a second field plate. The gate field plate is disposed on the semiconductor barrier layer. The source electrode is disposed on one side of the gate field plate, and the first field plate is disposed on the other side of the gate field plate and laterally spaced apart from the gate field plate. The second field plate covers the gate field plate and the first field plate and is electrically connected to the source electrode, where the area of the second field plate is larger than the sum of the area of the gate field plate and the area of the first field plate when perceived from a top-down perspective.

A GaN-based semiconductor device includes a substrate; a GaN channel layer disposed on the substrate; a AlGaN layer disposed on the GaN channel layer; a p-GaN gate layer disposed on the AlGaN layer; and a nitrogen-rich TiN hard mask layer disposed on the p-GaN gate layer. The nitrogen-rich TiN hard mask layer has a nitrogen-to-titanium (N/Ti) ratio that is greater than 1.0. A gate electrode layer is disposed on the nitrogen-rich TiN hard mask layer.

A superconductor transistor structure includes a source electrode and a drain electrode on a same plane as the source electrode. There is a channel region on top of the source and drain electrodes and configured to carry a current. A gate structure comprising a metallic material is on top of the channel region. The source and drain are located on a side that is opposite to that of the gate structure, with respect to the channel region.

An integrated semiconductor device includes a silicon body that includes <111> single crystal silicon, a semiconductor device that is disposed within the silicon body, a III-nitride body disposed on the silicon body, and a III-nitride device that is disposed within the III-nitride body, wherein the semiconductor device is operatively coupled to the III-nitride device.