An insulated gate silicon carbide semiconductor device includes: a drift layer of a first conductivity type on a silicon carbide substrate of 4H type with a {0001} plane having an off-angle of more than 0 as a main surface; a first base region; a source region; a trench; a gate insulating film; a protective diffusion layer; and a second base region. The trench sidewall surface in contact with the second base region is a surface having a trench off-angle of more than 0 in a <0001> direction with respect to a plane parallel to the <0001> direction. The insulated gate silicon carbide semiconductor device can relieve an electric field of a gate insulating film and suppress an increase in on-resistance and provide a method for manufacturing the same.

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 gate trench formed in the second semiconductor layer or in the second and first semiconductor layers, a gate electrode formed at the gate trench, and a source electrode and a drain electrode formed on the second semiconductor layer. The gate trench has terminal parts of a bottom of the gate trench formed shallower than a center part of the bottom. A part of a sidewall of the gate trench is formed of a surface including an a-plane. The center part of the bottom is a c-plane. The terminal parts of the bottom form a slope from the c-plane to the a-plane.

A transistor whose channel is formed in a semiconductor having dielectric anisotropy is provided. A transistor having a small subthreshold swing value is provided. A transistor having normally-off electrical characteristics is provided. A transistor having a low leakage current in an off state is provided. A semiconductor device includes an insulator, a semiconductor, and a conductor. In the semiconductor device, the semiconductor includes a region overlapping with the conductor with the insulator positioned therebetween, and a dielectric constant of the region in a direction perpendicular to a top surface of the region is higher than a dielectric constant of the region in a direction parallel to the top surface.

A silicon carbide semiconductor device includes a silicon carbide layer having a first main surface and a second main surface opposite to the first main surface. In the second main surface of the silicon carbide layer, a trench having a depth in a direction from the second main surface toward the first main surface is provided, and the trench has a sidewall portion where a second layer and a third layer are exposed and a bottom portion, where a first layer is exposed. A position of the bottom portion of the trench in a direction of depth of the trench is located on a side of the second main surface relative to a site located closest to the first main surface in a region where the second layer and the first layer are in contact with each other, or located as deep as the site in the direction of depth.

A semiconductor device having stable electric characteristics is provided. The transistor includes first to third oxide semiconductor layers, a gate electrode, and a gate insulating layer. The second oxide semiconductor layer has a portion positioned between the first and third oxide semiconductor layers. The gate insulating layer has a region in contact with a top surface of the third oxide semiconductor layer. The gate electrode overlaps with a top surface of the portion with the gate insulating layer positioned therebetween. The gate electrode faces a side surface of the portion in a channel width direction with the gate insulating layer positioned therebetween. The second oxide semiconductor layer includes a region having a thickness greater than or equal to 2 nm and less than 8 nm. The length in the channel width direction of the second oxide semiconductor layer is less than 60 nm.

A HEMT device comprising a M-plane III-Nitride material substrate, a p-doped epitaxial layer of III-Nitride material grown on said substrate; a recess etched in said p-doped epitaxial layer, the recess having a plane wall parallel to a polar plane of the III-Nitride material; a carrier carrying layer formed on said plane wall of the recess; a carrier supply layer formed on said at least one carrier carrying layer, such that a 2DEG region is formed in the carrier carrying layer at the interface with the carrier supply layer along said plane wall of the recess; a doped source region formed at the surface of said p-doped epitaxial layer such that the doped source region is separated from said 2DEG region by a channel region; a gate insulating layer formed on the channel region; and a gate contact layer formed on the gate insulating layer.

A method includes forming a dummy gate stack over a semiconductor substrate, wherein the semiconductor substrate is comprised in a wafer. The method further includes removing the dummy gate stack to form a recess, forming a gate dielectric layer in the recess, and forming a metal layer in the recess and over the gate dielectric layer. The metal layer has an n-work function. A portion of the metal layer has a crystalline structure. The method further includes filling a remaining portion of the recess with metallic materials, wherein the metallic materials are overlying the metal layer.

A semiconductor device structure is provided. The semiconductor device structure includes a substrate and a stacked wire structure formed over the substrate. The semiconductor device structure also includes a gate structure formed over a middle portion of the stacked wire structure and a source/drain (S/D) structure formed at two opposite sides of the stacked wire structure. The S/D structure includes a top surface, a sidewall surface, and a rounded corner between the top surface and the sidewall surface.

A method for fabricating substrate of a semiconductor device includes the steps of: providing a first silicon layer; forming a dielectric layer on the first silicon layer; bonding a second silicon layer to the dielectric layer; removing part of the second silicon layer and part of the dielectric layer to define a first region and a second region on the first silicon layer, wherein the remaining of the second silicon layer and the dielectric layer are on the second region; and forming an epitaxial layer on the first region of the first silicon layer, wherein the epitaxial layer and the second silicon layer comprise same crystalline orientation.

A method of fabricating a vertical field effect transistor including forming a first recess in a substrate; epitaxially growing a first drain from the first bottom surface of the first recess; epitaxially growing a second drain from the second bottom surface of a second recess formed in the substrate; growing a channel material epitaxially on the first drain and the second drain; forming troughs in the channel material to form one or more fin channels on the first drain and one or more fin channels on the second drain, wherein the troughs over the first drain extend to the surface of the first drain, and the troughs over the second drain extend to the surface of the second drain; forming a gate structure on each of the one or more fin channels; and growing sources on each of the fin channels associated with the first and second drains.