Abstract: A monocrystalline SiC substrate comprising a first surface and a second surface. The first surface comprises pinning regions and a device region. Each of the pinning regions is configured to provide a potential well which is capable to attract dislocations from a region surrounding said pinning region. The device region is configured to provide a part of the monocrystalline SiC substrate for manufacturing a semiconductor device. The device region is surrounded by the pinning regions, and a density of dislocations in a central portion of the device region is smaller than a density of dislocations in an edge of the device region due to the pinning regions. The pinning regions surrounding the device region attracts dislocations of the device region into the edge portion, so that the density of dislocations in the central portion is reduced. A yield of the semiconductor devices is improved.

Abstract: Provided are a high quality silicon carbide seed crystal, a silicon carbide crystal, a silicon carbide substrate, and a preparation method therefor. A high quality silicon carbide seed crystal is prepared, the dopant concentrations of a thermal insulation material, a graphite crucible, and a silicon carbide powder material are controlled, a specific crystal growth process and a wafer machining means are integrated, and a high quality silicon carbide substrate is obtained. The obtained silicon carbide substrate has a high crystalline quality and an extremely low amount of micropipes, screw dislocation density, and compound dislocation density; said substrate also has an extremely low p-type dopant concentration, exhibits superior electrical performance, and has a high surface quality.

Abstract: A silicon carbide single crystal wafer and a preparation method therefor, a silicon carbide crystal and a preparation method therefor, and a semiconductor device. The surface of the silicon carbide single crystal wafer is such that an included angle between a normal direction and a c direction is 0-8 degrees, and aggregated dislocations on the silicon carbide single crystal wafer are less than 300/cm2; the aggregated dislocation is a dislocation aggregated condition in which the distance between the geometric centers of any two corrosion pits in the corrosion pits obtained after corrosion of melted KOH is less than 80 microns. Even if the dislocation density is relatively high, the aggregated dislocation density is relatively small, thereby increasing the yield of a silicon carbide-based devices.