A transistor structure includes a source region and a drain region disposed in a substrate, extending along a first direction. A polysilicon layer is disposed over the substrate, extending along a second direction perpendicular to the first direction, wherein the polysilicon layer includes a first edge region, a channel region and a second edge region formed as a gate region between the source region and the drain region. The polysilicon layer has at least a first opening pattern at the first edge region having a first portion overlapping the gate region; and at least a second opening pattern at the second edge region having a second portion overlapping the gate region.

An integrated MOSFET-JFET device made from a Silicon-Carbide (SiC) wafer has N+ source, P body diode, and upper N regions that form vertical MOSFETs on the sidewalls of polysilicon gates. An N substrate under the upper N region forms a drift region that is pinched by the JFET to limit saturation current. Trenches are formed between MOSFETs. JFETs are formed by doping the bottom and sidewalls of the trenches to form P+ taps to the N substrate. P islands within the N substrate are formed underneath the P+ taps. These P islands are wider near the surface but are successively narrower with increased vertical spacing deeper into the N substrate. This P-island tapering provides a tapered shape to the JFET depletion region that pinches the MOSFET drift region in the N substrate to limit saturation current and yet reduce linear-region ON resistance.

A method for manufacturing semiconductor device according to an embodiment includes: forming a first metal oxide layer containing aluminum as a main component above a substrate; forming an oxide semiconductor layer above the first metal oxide layer; forming a gate insulating layer above the oxide semiconductor layer; forming a second metal oxide layer containing aluminum as a main component above the gate insulating layer; performing a heat treatment in a state where the second metal oxide layer is formed above the gate insulating layer; removing the second metal oxide layer after the heat treatment; and forming a gate electrode above the gate insulating layer.

A SiC semiconductor device includes a substrate of a first conductivity type, a buffer layer of the first conductivity type on the substrate, a low-concentration layer on the buffer layer, a first deep layer and a JFET portion on the low-concentration layer, a current diffusion layer of the first conductivity type disposed on the JFET portion and having an impurity concentration higher than the low-concentration layer, a second deep layer of a second conductivity type disposed on the first deep layer, a base layer of the second conductivity type disposed on the current diffusion layer and the second deep layer, an impurity region of the first conductivity type disposed in a surface layer portion of the base layer, and a trench gate structure penetrating the impurity region and the base layer and reach the current diffusion layer. The JFET portion is formed with defect portions.

A field-plate trench FET having a drain region, an epitaxial layer, a source region, a gate conductive layer formed in a trench, a field-plate dielectric layer formed on vertical sidewalls of the trench, a well region formed below the trench, a source contact and a gate contact. When the well region is in direct physical contact with the gate conductive layer, the field-plate trench FET can be used as a normally-on device working depletion mode, and when the well region is electrically isolated from the gate conductive layer by the field-plate layer, the field-plate trench FET can be used as a normally-off device working in an accumulation-depletion mode.

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 transistor having high field-effect mobility is provided. In order that an oxide semiconductor layer through which carriers flow is not in contact with a gate insulating film, a buried channel structure in which the oxide semiconductor layer through which carriers flow is separated from the gate insulating film is employed. Specifically, an oxide semiconductor layer having high conductivity is provided between two oxide semiconductor layers. Further, an impurity element is added to the oxide semiconductor layer in a self-aligned manner so that the resistance of a region in contact with an electrode layer is reduced. Further, the oxide semiconductor layer in contact with the gate insulating layer has a larger thickness than the oxide semiconductor layer having high conductivity.

The invention relates to a DEPFET comprising: a semiconductor substrate (100) of a first conduction type, which has a first main surface (101) and a second main surface (102), which are opposite one another; a source terminal region (1s) of a second conduction type on the first main surface (101); a drain terminal region (1d) of a second conduction type; a channel region (10), which is arranged between the source terminal region (1s) and the drain terminal region (1d); a gate electrode (11), which is separated from the channel region (10) by a gate insulator (6); a rear activation region (104) of a second conduction type, which is formed on the second main surface (102); and a substrate doping increase region (2) of a first conduction type, which is formed at least under the source terminal region (1s) and under the channel region (10), the substrate doping increase region (2) having a signal charge control region (20) of the first conduction type below the gate electrode (11), in which signal charge control region the effective doping dose has a higher value than at other points of the substrate doping increase region (2) below the gate electrode.

A silicon carbide semiconductor device includes a first load electrode disposed on a first surface of a silicon carbide semiconductor body, a first doped region disposed in the silicon carbide semiconductor body and electrically connected to the first load electrode, and an insulated gate field effect transistor electrically connected in series with the first doped region, the insulated gate field effect transistor including a source region and a body region, the body region being electrically connected to the first load electrode, wherein a geometry and dopant concentration of the first doped region is such that a resistance of the first doped region increases by at least a factor of two as load current in the insulated gate field effect transistor rises.

A semiconductor device is provided, including a substrate having a first epitaxial layer arranged thereon and a voltage blocking element arranged in the first epitaxial layer, a second epitaxial layer arranged on the first epitaxial layer, and a vertical switching element arranged in the second epitaxial layer.