A high electron mobility transistor (HEMT) includes a substrate; a source on the substrate; a drain on the substrate spaced from the source; and a gate between the source and the drain, wherein the gate has a stem contacting the substrate, the stem having a source side surface and a drain side surface, wherein a source side angle is defined between the source side surface and an upper planar surface of the substrate and a drain side angle is defined between the drain side surface and the upper planar surface of the substrate, and wherein the source side angle and the drain side angle are asymmetric. Methods for making the HEMT are also disclosed.

A semiconductor device for power amplification includes: a source electrode, a drain electrode, and a gate electrode disposed above a semiconductor stack structure including a first nitride semiconductor layer and a second nitride semiconductor layer; and a source field plate that is disposed above the semiconductor stack structure between the gate electrode and the drain electrode, and has a same potential as a potential of the source electrode. The source field plate has a staircase shape, and even when length LF2 of an upper section is increased for electric field relaxation, an increase in parasitic capacitance Cds generated between the source field plate and a 2DEG surface is inhibited.

A semiconductor device and the method of manufacturing the same are provided. The semiconductor device comprises a well region, a first doped region, a drain region, a source region and a gate electrode. The first doped region of a first conductivity type is located at a first side within the well region. The drain region of the first conductivity type is within the first doped region. The source region of the first conductivity type is at a second side within the well region, wherein the second side being opposite to the first side. The gate electrode is over the well region and between the source region and the drain region. A surface of the drain region and a surface of the source region define a channel and the surface of the source region directly contacts the well region.

A high electron mobility transistor (HEMT) includes a substrate; a source on the substrate; a drain on the substrate spaced from the source; and a gate between the source and the drain, wherein the gate has a stem contacting the substrate, the stem having a source side surface and a drain side surface, wherein a source side angle is defined between the source side surface and an upper planar surface of the substrate and a drain side angle is defined between the drain side surface and the upper planar surface of the substrate, and wherein the source side angle and the drain side angle are asymmetric. Methods for making the HEMT are also disclosed.

A high-threshold-voltage normally-off high-electron-mobility transistor (HEMT) includes a nucleation layer and an epitaxial layer are grown sequentially on a substrate; a barrier layer, a source, and a drain above the epitaxial layer; the barrier layer and the epitaxial layer form a heterojunction structure, and the contact interface therebetween is induced by polarization charges to generate two-dimensional electron gas. The HEMT includes a passivation layer above the barrier layer; a gate cap layer above the gate region barrier layer; the upper part of the gate cap layer is subjected to surface plasma oxidation to form an oxide dielectric layer, or a single-layer or multiple gate dielectric insertion layer is directly deposited thereon. The HEMT includes a gate is located above the gate dielectric insertion layer; the gate is in contact with the passivation layer; and a field plate extends from the gate to the drain on the passivation layer.

A method of forming one or more contact regions in a high-voltage field effect transistor (HFET) includes providing a semiconductor material, including a first active layer and a second active layer, with a gate dielectric disposed on a surface of the semiconductor material. A first contact to the semiconductor material is formed that extends through the second active layer into the first active layer, and a passivation layer is deposited, where the gate dielectric is disposed between the passivation layer and the second active layer. An interconnect is formed extending through the first passivation layer and coupled to the first contact. An interlayer dielectric is deposited proximate to the interconnect, and a plug is formed extending into the interlayer dielectric and coupled to the first portion of the interconnect.

A method of forming one or more contact regions in a high-voltage field effect transistor (HFET) includes providing a semiconductor material, including a first active layer and a second active layer, with a gate dielectric disposed on a surface of the semiconductor material. A first contact to the semiconductor material is formed that extends through the second active layer into the first active layer, and a passivation layer is deposited, where the gate dielectric is disposed between the passivation layer and the second active layer. An interconnect is formed extending through the first passivation layer and coupled to the first contact. An interlayer dielectric is deposited proximate to the interconnect, and a plug is formed extending into the interlayer dielectric and coupled to the first portion of the interconnect.

A method of forming one or more contact regions in a high-voltage field effect transistor (HFET) includes providing a semiconductor material, including a first active layer and a second active layer, with a gate dielectric disposed on a surface of the semiconductor material. A first contact to the semiconductor material is formed that extends through the second active layer into the first active layer, and a passivation layer is deposited, where the gate dielectric is disposed between the passivation layer and the second active layer. An interconnect is formed extending through the first passivation layer and coupled to the first contact. An interlayer dielectric is deposited proximate to the interconnect, and a plug is formed extending into the interlayer dielectric and coupled to the first portion of the interconnect.

A high electron mobility transistor includes a set of electrodes, such as a source, a drain, a top gate, and a side gate, and includes a semiconductor structure having a fin extending between the source and the drain. The top gate is arranged on top of the fin, and the side gate is arranged on a sidewall of the fin at a distance from the top gate. The semiconductor structure includes a cap layer positioned beneath the top gate and a channel layer arranged beneath the cap layer for providing electrical conduction. The cap layer includes nitride-based semiconductor material to enable a heterojunction forming a carrier channel between the source and the drain.

Semiconductor devices having metallic source and drain regions are described. For example, a semiconductor device includes a gate electrode stack disposed above a semiconducting channel region of a substrate. Metallic source and drain regions are disposed above the substrate, on either side of the semiconducting channel region. Each of the metallic source and drain regions has a profile. A first semiconducting out-diffusion region is disposed in the substrate, between the semiconducting channel region and the metallic source region, and conformal with the profile of the metallic source region. A second semiconducting out-diffusion region is disposed in the substrate, between the semiconducting channel region and the metallic drain region, and conformal with the profile of the metallic drain region.