Silicon carbide single crystal wafer, crystal, preparation methods therefor, and semiconductor device

A silicon carbide monocrystalline wafer, wherein:

• an included angle between a normal direction of a surface of the silicon carbide monocrystalline wafer and a direction of a c-axis ranges from 0° to 8°;
• a density of dislocations on the surface of the silicon carbide monocrystalline wafer is higher than 1000/cm2;
• and
• wherein a density of clustered dislocations is equal to a quantity of clustered dislocations divided by an area of the silicon carbide monocrystalline wafer, and the quantity of clustered dislocations is defined as a half of a total quantity of first dislocations among the dislocations on the surface of the silicon carbide monocrystalline wafer;
• and
• wherein the first dislocations comprise any dislocation, among target dislocations on the surface, which satisfies:
• there is at least one etching pit located within 80 μm from an etching pit of said dislocation when the surface of the silicon carbide monocrystalline wafer is etched using molten potassium hydroxide, the at least one etching pit is of any dislocation other than said first dislocation among the target dislocations, and the etching pit of said first dislocation and the at least one etching pit are exposed on the surface of the silicon carbide monocrystalline wafer due to etching of the molten potassium hydroxide;
• wherein when the target dislocations comprise all threading screw dislocation, all threading edge dislocation, and all basal plane dislocation on the surface, the density of clustered dislocations on the surface of the silicon carbide monocrystalline wafer is lower than 300/cm2.