Provided is a manufacturing method for manufacturing a SiC substrate having a flattened surface, including etching the surface of the SiC substrate by irradiating the surface of the SiC substrate with atomic hydrogen while the SiC substrate having an off angle is heated. In the etching, the SiC substrate may be heated within a range of 800° C. or higher and 1200° C. or lower.

A semiconductor device of the present invention includes a semiconductor layer, a gate trench that defines a source region of a first conductivity type in the semiconductor layer, a channel region of a second conductivity type of a lower part of the source region, a source trench that passes through the source region and the channel region, an impurity region of the second conductivity type of a bottom part and a side part of the source trench, a source electrode on the semiconductor layer, and a highly-concentrated impurity region of the second conductivity type, the highly-concentrated impurity region having a contact portion connected to the source electrode at a surface of the semiconductor layer, the highly-concentrated impurity region passing through the source region and extending to a position deeper than the source region, the highly-concentrated impurity region having a concentration higher than the impurity region.

According to one embodiment, a semiconductor device includes first to fourth semiconductor regions, first and second electrodes, and a first insulating film. The first semiconductor region includes first and second partial regions, and an intermediate partial region. The first electrode is separated from the first partial region. The second electrode includes first and second conductive regions. The second semiconductor region is provided between the first conductive region and the first electrode. The third semiconductor region is provided between the first conductive region and at least a portion of the second semiconductor region. The fourth semiconductor region includes third and fourth partial regions. The fourth partial region is positioned between the first conductive region and the first electrode. The first insulating film is provided, between the fourth partial region and the first electrode, and between the second semiconductor region and the first electrode.

A method for forming a semiconductor device includes: forming a trench structure with trenches in an inner region and an edge region of a SiC semiconductor body such that the trench structure extends from a first surface of the semiconductor body through a second semiconductor layer into a first semiconductor layer and such that the trench structure, in the second semiconductor layer, forms mesa regions; and forming at least one transistor cell at least partially in each of the mesa regions in the inner region. Forming each transistor cell includes forming at least one compensation region. Forming the compensation region includes implanting dopant atoms of a second doping type via sidewalls of the trenches into the mesa regions in the inner region. Forming the compensation region in each mesa region in the inner region includes at least partially covering the edge region with an implantation mask.

A silicon carbide semiconductor device includes a silicon carbide substrate having a first main surface and a second main surface opposite to the first main surface. A gate trench is provided in the first main surface. The gate trench is defined by side surfaces and a bottom surface. The side surfaces penetrate the source region and the body region to reach the drift region. The bottom surface connects to the side surfaces. The gate trench extends in a first direction parallel to the first main surface. The silicon carbide substrate further includes an electric field relaxation region that is the second conductive type, the electric field relaxation region being provided between the bottom surface and the second main surface and extending in the first direction, and a connection region that is the second conductive type, the connection region electrically connecting a contact region to the electric field relaxation region. In a plan view in a direction normal to the first main surface, the gate trench and the electric field relaxation region are disposed on a virtual line that extends in the first direction, and the connection region is in contact with the electric field relaxation region on the virtual line.

A method of manufacturing a silicon carbide substrate having a parallel pn layer. The method includes preparing a starting substrate containing silicon carbide, forming a first partial parallel pn layer on the starting substrate by a trench embedding epitaxial process, stacking a second partial parallel pn layer by a multi-stage epitaxial process on the first partial parallel pn layer, and stacking a third partial parallel pn layer on the second partial parallel pn layer by another trench embedding epitaxial process. Each of the first, second and third partial parallel pn layers is formed to include a plurality of first-conductivity-type regions and a plurality of second-conductivity-type regions alternately disposed in parallel to a main surface of the silicon carbide substrate. The first-conductivity-type regions of the first and third partial parallel pn layers face each other in a depth direction of the silicon carbide substrate, and the second-conductivity-type regions partial parallel pn layers face each other in the depth direction.

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.

Junction field effect transistors (JFETs) and related manufacturing methods are disclosed herein. A disclosed JFET includes a vertical channel region located in a mesa and a first channel control region located on a first side of the mesa. The first channel control region is at least one of a gate region and a first base region. The JEFT also includes a second base region located on a second side of the mesa and extending through the mesa to contact the vertical channel region. The vertical channel can be an implanted vertical channel. The vertical channel can be asymmetrically located in the mesa towards the first side of the mesa.

A silicon carbide semiconductor device includes a silicon carbide (SiC) substrate having a SiC epitaxial layer disposed over a surface of the SiC substrate, the SiC substrate having a first conductivity and the SiC epitaxial layer having the first conductivity. A contact region and a well region are formed in the SiC epitaxial layer, the contact region and the well region have a doping level of a second conductivity opposite the first conductivity. The contact region lies completely within the well region, is not in contact with a region having the first conductivity and has edges recessed from edges of the well region.

A semiconductor device includes a first silicon carbide region of a first conductivity type, a second silicon carbide region of a second conductivity type on the first region, and a third silicon carbide region of a second conductivity type on the second region. Fourth and fifth silicon carbide region of the first conductivity type are on the third region. A first electrode has a first portion between the fourth region and fifth region in a first direction. A metal silicide layer is between the first portion and the third region, between the first portion and the fourth region in the first direction, and between the first portion and the fifth silicon carbide region in the first direction.