Disclosed herein are approaches for forming a SiC MOSFET including at least one trench with rounded corners. In one approach, a method may include providing a masking layer over a silicon carbide (SiC) layer, wherein an opening is formed in the masking layer, and providing a sidewall spacer along a sidewall of the opening of the masking layer. The method may further include forming an implant region within the SiC layer by directing ions through the opening defined by the sidewall spacer, performing a first etch to the SiC layer, wherein the first etch forms a central recess and a set of shoulder regions adjacent the central recess, and performing a second etch to remove the set of shoulder regions.

A wafer having a first surface, an opposite second surface, and an outer circumferential surface that includes a curved part curved outward in a protruding manner is separated into two wafers. Part of the wafer is removed along the curved part, and a separation origin is formed inside the wafer by positioning the focal point of a laser beam with a wavelength having transmissibility with respect to the wafer inside the wafer and executing irradiation with the laser beam while the focal point and the wafer are relatively moved in such a manner that the focal point is kept inside the wafer. The wafer is separated into two wafers by an external force.

An embodiment relates to a method comprising obtaining a SiC substrate comprising a N+ substrate and a N drift layer; depositing a first hard mask layer on the SiC substrate and patterning the first hard mask layer; performing a p-type implant to form a p-well region; depositing a second hard mask layer on top of the first hard mask layer; performing an etch back of at least the second hard mask layer to form a sidewall spacer; implanting N type ions to form a N+ source region that is self-aligned; and forming a MOSFET.

A power semiconductor device includes a silicon carbide substrate and at least a first layer or region formed above the substrate. The silicon carbide substrate has a pattern of pits formed thereon. The device further comprising an ohmic metal disposed at least in the pits to form low-resistance ohmic contacts.

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.

Implementations of a method of singulating a plurality of semiconductor die may include: forming a damage layer beneath a surface of a die street where the die street connects a plurality of semiconductor die and the plurality of semiconductor die are formed on a semiconductor substrate. The method may also include sawing the die street after forming the damage layer to singulate the plurality of semiconductor die.

Implementations of a method of forming a plurality of semiconductor devices on a semiconductor substrate may include: providing a semiconductor substrate having a first surface, a second surface, a size, and a thickness where the second surface opposes the first surface and the thickness is between the first surface and the second surface. The method may include processing the semiconductor substrate through a plurality of semiconductor device fabrication processes to form a plurality of semiconductor devices on the first surface. The thickness may be between 100 microns and 575 microns and the size may be 150 mm. The semiconductor substrate may not be coupled with a carrier or support.

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 selectivity can be improved in a desirable manner when etching a processing target object containing silicon carbide. An etching method of processing the processing target object, having a first region containing silicon carbide and a second region containing silicon nitride and in contact with the first region, includes etching the first region to remove the first region atomic layer by atomic layer by repeating a sequence comprising: generating plasma from a first gas containing nitrogen to form a mixed layer containing ions contained in the plasma generated from the first gas in an atomic layer of an exposed surface of the first region; and generating plasma from a second gas containing fluorine to remove the mixed layer by radicals contained in the plasma generated from the second gas.

A semiconductor device may include: an n type of layer disposed on a first surface of a substrate; a p+ type of region disposed on the first surface of the substrate; a p type of region disposed at a top portion of the n type of layer; a first electrode disposed on the p+ type of region and the p type of region; and a second electrode disposed on a second surface of the substrate, wherein the side surface of the p+ type of region and the side surface of the n type of layer are in contact, and the thickness of the p+ type of region is the same as the thickness of the n type of layer and the thickness of the p type of region.