A method of making a semiconductor including a step of preparing a base substrate; a first step of epitaxially growing a single crystal of a group III nitride semiconductor having a top surface with (0001) plane exposed, directly on the main surface of the base substrate, forming a plurality of concaves composed of inclined interfaces other than the (0001) plane on the top surface, gradually expanding the inclined interfaces toward an upper side of the main surface of the base substrate, making the (0001) plane disappear from the top surface, and growing a first layer whose surface is composed only of the inclined interfaces; and a second step of epitaxially growing a single crystal of a group III nitride semiconductor on the first layer, making the inclined interfaces disappear, and growing a second layer having a mirror surface, and a semiconductor made thereby.

A semiconductor device according to the present disclosure includes a substrate including a plurality of atomic steps that propagate along a first direction, and a transistor disposed on the substrate. The transistor includes a channel member extending a second direction perpendicular to the first direction, and a gate structure wrapping around the channel member.

A silicon carbide ingot is cut using a wire. The silicon carbide ingot has a polytype of 4H—SiC. The silicon carbide ingot includes a top surface, a bottom surface opposite to the top surface, and a side surface between the top surface and the bottom surface. A direction from the bottom surface toward the top surface is a direction parallel to a [0001] direction or a direction inclined by less than or equal to 8° relative to the [0001] direction. In the cutting of the silicon carbide ingot, the silicon carbide ingot is cut from the side surface at a (000-1) plane side along a straight line parallel to a direction within ±5° relative to a direction that bisects an angle formed by a [1-100] direction and a [11-20] direction when viewed in the direction from the bottom surface toward the top surface.

A nitride semiconductor substrate including a group III nitride semiconductor crystal and having a main surface, wherein a low index crystal plane is (0001) plane curved in a concave spherical shape to the main surface, and the off-angle (θ.sub.m, θ.sub.a) at a position (x, y) in the main surface approximated by x representing a coordinate in a direction along <1-100> axis, y is a coordinate in a direction along <11-20> axis, (0, 0) represents a coordinate (x, y) of the center, θ.sub.m represents a direction component along <1-100> axis in an off-angle of <0001> axis with respect to a normal, θ.sub.a represents a direction component along <11-20> axis in the off-angle, (M.sub.1, A.sub.1) represents a rate of change in the off-angle (θ.sub.m, θ.sub.a) with respect to the position (x, y) in the main surface, and (M.sub.2, A.sub.2) represents the off-angle (θ.sub.m, θ.sub.a) at the center.

An epitaxial wafer including a wafer having one surface and an other surface, and an epitaxial layer formed on the one surface of the wafer, wherein a roughness skewness (Rsk) of the one surface is −3 nm to 3 nm, and a roughness average (Ra) of an edge area of the one surface is different from that of a central area of the one surface by −2 nm to 2 nm when the edge area of the one surface is defined as an area between 13.3% and 32.1% of the radius of the wafer in a direction from the edge of the one surface toward the center thereof and the central area of the one surface is defined as an area at 9.4% of the radius of the wafer from the center of the one surface.

A silicon carbide ingot is cut using a wire. The silicon carbide ingot has a polytype of 4HSiC. The silicon carbide ingot includes a top surface, a bottom surface opposite to the top surface, and a side surface between the.top surface and the bottom surface. A direction from the bottom surface toward the top surface is a direction parallel to a [0001] direction or a direction inclined by less than or equal to 8 relative to the [0001] direction. In the cutting of the silicon carbide ingot, the silicon carbide ingot is cut from the side surface at a (000-1) plane side along a straight line parallel to a direction within 5 relative to a direction that bisects an angle formed by a [1-100] direction and a [11-20] direction when viewed in the direction from the bottom surface toward the top surface.

A shaped crystalline ingot for an ion cleaving process has a major surface that is substantially planar, a first side face that is substantially planar along a first direction orthogonal to the major surface, and a second side face that is substantially planar along a second direction orthogonal to the major surface. The ion cleaving process is a process in which ions are implanted into the shaped crystalline ingot to form a cleave plane that separates a substrate comprising the major surface from the shaped crystalline ingot.

A method of manufacturing a gallium nitride substrate, the method including forming a first buffer layer on a silicon substrate such that the first buffer layer has one or more holes therein; forming a second buffer layer on the first buffer layer such that the second buffer layer has one or more holes therein; and forming a GaN layer on the second buffer layer, wherein the one or more holes of the first buffer layer are filled by the second buffer layer.

The present invention relates to a chamfered silicon carbide substrate which is essentially monocrystalline, and to a corresponding method of chamfering a silicon carbide substrate. A silicon carbide substrate according to the invention comprises a main surface (102), wherein an orientation of said main surface (102) is such that a normal vector ({right arrow over (O)}) of the main surface (102) includes a tilt angle with a normal vector ({right arrow over (N)}) of a basal lattice plane (106) of the substrate, and a chamfered peripheral region (110), wherein a surface of the chamfered peripheral region includes a bevel angle with said main surface, wherein said bevel angle is chosen so that, in more than 75% of the peripheral region, normal vectors ({right arrow over (F)}_i) of the chamfered peripheral region (110) differ from the normal vector of the basal lattice plane by less than a difference between the normal vector of the main surface and the normal vector of the basal lattice plane of the substrate.

A nitride semiconductor substrate including a group III nitride semiconductor crystal and having a main surface, wherein a low index crystal plane is (0001) plane curved in a concave spherical shape to the main surface, and the off-angle (?.sub.m, ?.sub.a) at a position (x, y) in the main surface approximated by x representing a coordinate in a direction along <1-100> axis, y is a coordinate in a direction along <11-20> axis, (0, 0) represents a coordinate (x, y) of the center, ?.sub.m represents a direction component along <1-100> axis in an off-angle of <0001> axis with respect to a normal, ?.sub.a represents a direction component along <11-20> axis in the off-angle, (M.sub.1, A.sub.1) represents a rate of change in the off-angle (?.sub.m, ?.sub.a) with respect to the position (x, y) in the main surface, and (M.sub.2, A.sub.2) represents the off-angle (?.sub.m, ?.sub.a) at the center.