An insulated-gate semiconductor device, which has trenches arranged in a chip structure, the trenches defining both sidewalls in a first and second sidewall surface facing each other, includes: a first unit cell including a main-electrode region in contact with a first sidewall surface of a first trench, a base region in contact with a bottom surface of the main-electrode region and the first sidewall surface, a drift layer in contact with a bottom surface of the base region and the first sidewall surface, and a gate protection-region in contact with the second sidewall surface and a bottom surface of the first trench; and a second unit cell including an operation suppression region in contact with a first sidewall surface and a second sidewall surface of a second trench, wherein the second unit cell includes the second trench located at one end of an array of the trenches.

A method of forming a transistor device includes providing a drift layer having a first conductivity type, forming a first region in the drift layer, the first region having a second conductivity type that is opposite the first conductivity type, forming a body layer on the drift layer including the first region, forming a source layer on the body layer, forming a trench in the source layer and the body layer above the first region and extending into the first region, forming a gate insulator on the inner sidewall of the trench, and forming a gate contact on the gate insulator.

Silicon carbide on insulator is provided by bonding bulk silicon carbide to a substrate with an oxide-oxide fusion bond, followed by thinning the bulk silicon carbide as needed.

According to one embodiment, a method for manufacturing a device includes a first process, a second process, a third process, and a fourth process. The first process includes providing a structure body at a first surface of a substrate. The substrate is light-transmissive and has a second surface. A light transmissivity of the structure body is lower than a light transmissivity of the substrate. The second process includes providing a negative-type photoresist at the second surface. The third process includes irradiating the substrate with light to expose a portion of the photoresist. The light is irradiated in a first direction from the first surface toward the second surface. The light passes through the substrate. The fourth process includes developing the photoresist to remain the portion of the photoresist in a state of being adhered to the second surface and to remove other portion of the photoresist.

A vertical power transistor including a semiconductor substrate, which has a front side on which at least one epitaxial layer, one channel layer, and one source layer are situated. The epitaxial layer includes a first semiconductor material which has a first doping, and a plurality of first trenches and second trenches, the first trenches and the second trenches being situated alternatingly and extending perpendicularly at least into the channel layer starting from a surface of the source layer, an area extending perpendicularly into the epitaxial layer, starting from an underside of each first trench bottom, the area including a second semiconductor material which encompasses a second doping.

A silicon carbide semiconductor element includes n-type silicon carbide epitaxial layers formed on an n.sup.+-type silicon carbide semiconductor substrate, plural p base layers selectively formed in surfaces of the silicon carbide epitaxial layers, a p-type silicon carbide epitaxial layer formed in the silicon carbide epitaxial layer, and a trench penetrating at least the silicon carbide epitaxial layer. The silicon carbide semiconductor element also includes, in a portion of the silicon carbide epitaxial layer, a mesa portion exposing the p base layer. The silicon carbide semiconductor element further includes, between consecutive mesa side faces of the mesa portion, a flat portion substantially parallel to the silicon carbide substrate. The remaining thickness of the exposed p base layer is larger than 0.5 m and smaller than 1.0 m.

An electrical isolation process, includes receiving a substrate including a layer of carbon-rich material on silicon, and selectively removing regions of the substrate to form mutually spaced islands of the carbon-rich material on the silicon. The layer of carbon-rich material on silicon includes the layer of carbon-rich material on an electrically conductive layer of silicon on an electrically insulating material. Selectively removing regions of the substrate includes removing the carbon-rich material and at least a portion of the electrically conductive layer of silicon from those regions to provide electrical isolation between the islands of carbon-rich material on silicon.

A method of catalyst-assisted chemical etching with a vapor-phase etchant has been developed. In one approach, a semiconductor substrate including a patterned titanium nitride layer thereon is heated, and an oxidant and an acid are evaporated to form a vapor-phase etchant comprising an oxidant vapor and an acid vapor. The semiconductor substrate and the patterned titanium nitride layer are exposed to the vapor-phase etchant during the heating of the semiconductor substrate. The vapor-phase etchant diffuses through the patterned titanium nitride layer, and titanium nitride-covered regions of the semiconductor substrate are etched. Thus, an etched semiconductor structure is formed.

An optical element is provided. The optical element includes a substrate; a plurality of metal grids formed on the substrate; an oxide layer formed on the substrate between the plurality of metal grids; and a plurality of organic layers formed on the plurality of metal grids, wherein the width of the organic layer is greater than the width of the metal grid, and there is at least one gap between the organic layer and the oxide layer.

All of intervals between adjacent p type guard rings are set to be equal to or less than an interval between p type deep layers. As a result, the interval between the p type guard rings becomes large, i.e., the trenches are formed sparsely, so that the p type layer is prevented from being formed thick at the guard ring portion when the p type layer is epitaxially grown. Therefore, by removing the p type layer in the cell portion at the time of the etch back process, it is possible to remove the p type layer without leaving any residue in the guard ring portion. Therefore, when forming the p type deep layer, the p type guard ring and the p type connection layer by etching back the p type layer, the residue of the p type layer is restricted from remaining in the guard ring portion.