A gate electrode includes a main portion formed of a gate electrode material, and a gate electrode barrier layer disposed between the main portion and a barrier layer and formed of a conductive material that prevents the gate electrode material from diffusing into the barrier layer. A surface of the main portion in a region above a first insulating layer faces a periphery without a layer of the conductive material being formed.

Structures, devices and methods are provided for forming an interface protection layer (204) adjacent to a fully or partially recessed gate structure (202) of a group III nitride, a metal-insulator-semiconductor high-electron-mobility transistor (MIS-HEMT) device or a metal-insulator-semiconductor field-effect transistor (MIS-FET) device, and forming agate dielectric (114) disposed the interface protection layer (204).

The on-resistance of each of field effect transistors having different planar sizes is reduced. A semiconductor device includes first and second field effect transistors mounted on a semiconductor substrate and an insulating layer provided on a main surface of the semiconductor substrate. Here, each of the first and second field effect transistors includes a pair of main electrodes which are separated from each other and provided on the main surface of the semiconductor substrate, a cavity part which is provided in the insulating layer between the pair of main electrodes, and a gate electrode which has a head part positioned on the insulating layer and a body part that penetrates the insulating layer from the head part and protrudes toward the cavity part and in which the head part is wider than the body part. Here, the width of the cavity part of the second field effect transistor is different from the width of the cavity part of the first field effect transistor.

A semiconductor device includes: a compound semiconductor layer having a first compound semiconductor layer and a second compound semiconductor layer having a higher melting point than the first compound semiconductor layer; and an insulation gate on the second compound semiconductor layer. The compound semiconductor layer further includes: a drift region; a source region; and a body region between the drift region and the source region. The insulation gate faces the body region. The body region bridges over both the first compound semiconductor layer and the second compound semiconductor layer.

Disclosed herein are IC structures, packages, and devices that include planar III-N transistors with wrap-around gates and/or one or more wrap-around source/drain (S/D) contacts. An example IC structure includes a support structure (e.g., a substrate) and a planar III-N transistor. The transistor includes a channel stack of a III-N semiconductor material and a polarization material, provided over the support structure, a pair of S/D regions provided in the channel stack, and a gate stack of a gate dielectric material and a gate electrode material provided over a portion of the channel stack between the S/D regions, where the gate stack at least partially wraps around an upper portion of the channel stack.

A method for manufacturing a vertical JFET includes providing a III-nitride substrate having a first conductivity type; forming a first III-nitride layer coupled to the III-nitride substrate, wherein the first III-nitride layer is characterized by a first dopant concentration and the first conductivity type; forming a plurality of trenches within the first III-nitride layer, wherein the plurality of trenches extend to a predetermined depth; epitaxially regrowing a second III-nitride structure in the trenches, wherein the second III-nitride structure is characterized by a second conductivity type; forming a plurality of III-nitride fins, each coupled to the first III-nitride layer, wherein the plurality of III-nitride fins are separated by one of a plurality of recess regions; epitaxially regrowing a III-nitride gate layer in the recess regions, wherein the III-nitride gate layer is coupled to the second III-nitride structure, and wherein the III-nitride gate layer is characterized by the second conductivity type.

A transistor comprises a base layer that includes a channel region, wherein the base layer and the channel region include group III-V semiconductor material. A gate stack is above the channel region, the gate stack comprises a gate electrode and a composite gate dielectric stack, wherein the composite gate dielectric stack comprises a first large bandgap oxide layer, a low bandgap oxide layer, and a second large bandgap oxide layer to provide a programmable voltage threshold. Source and drain regions are adjacent to the channel region.

A method for manufacturing a vertical JFET includes providing a III-nitride substrate having a first conductivity type and forming a first III-nitride layer coupled to the III-nitride substrate. The first III-nitride layer is characterized by a first dopant concentration and the first conductivity type. The method also includes forming a plurality of trenches within the first III-nitride layer and epitaxially regrowing a second III-nitride structure in the trenches. The second III-nitride structure is characterized by a second conductivity type. The method further includes forming a plurality of III-nitride fins, each coupled to the first III-nitride layer, wherein the plurality of III-nitride fins are separated by one of a plurality of recess regions, and epitaxially regrowing a III-nitride gate layer in the recess regions. The III-nitride gate layer is coupled to the second III-nitride structure and the III-nitride gate layer is characterized by the second conductivity type.

The present invention relates to an epitaxial structure of N-face group III nitride, its active device, and its gate protection device. The epitaxial structure of N-face AlGaN/GaN comprises a silicon substrate, a buffer layer (C-doped) on the silicon substrate, an i-GaN (C-doped) layer on the buffer layer (C-doped), an i-Al.sub.yGaN buffer layer on the i-GaN (C-doped) layer, an i-GaN channel layer on the i-Al.sub.yGaN buffer layer, and an i-Al.sub.xGaN layer on the i-GaN channel layer, where x=0.1˜0.3 and y=0.05˜0.75. By connecting a depletion-mode (D-mode) AlGaN/GaN high electron mobility transistor (HEMT) to the gate of a p-GaN gate enhancement-mode (E-mode) AlGaN/GaN HEMT in device design, the gate of the p-GaN gate E-mode AlGaN/GaN HEMT can be protected under any gate voltage.

A semiconductor device includes a first semiconductor layer formed of a nitride semiconductor, on a substrate; a second semiconductor layer formed of a nitride semiconductor, on the first semiconductor layer; a source electrode and a drain electrode formed on the second semiconductor layer; a first insulating film formed on the second semiconductor layer; a second insulating film formed on the first insulating film; and a gate electrode formed on the second insulating film. The first insulating film includes a nitride film formed on a side of the second semiconductor layer, and an oxynitride film formed on the nitride film, and the second insulating film is formed of an oxide.