Silicon carbide single crystal wafer, and methods for manufacturing silicon carbide single crystal ingot and the silicon carbide single crystal wafer
AssigneeDenso Corporation
InventorsIsaho KAMATA, Hidekazu TSUCHIDA, Norihiro HOSHINO, Yuichiro TOKUDA, Takeshi OKAMOTO
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Abstract
In a silicon carbide single crystal wafer, a dislocation density contained therein is 3500 dislocations/cm2 or less, and a difference of the dislocation density among a wafer central part, a wafer peripheral part and a wafer intermediate part is less than 50% of an average value thereof.
Claims6
A silicon carbide single crystal wafer in which:
- a dislocation density is 3500 dislocations/cm2 or less;
- and
- a difference of the dislocation density among a wafer central part, a wafer peripheral part and a wafer intermediate part is less than 50% of an average value thereof.
A silicon carbide single crystal wafer manufactured by a gas growth method, in which:
- an edge dislocation density is 3000 dislocations/cm2 or less;
- and
- a difference of the edge dislocation density among a wafer central part, a wafer peripheral part and a wafer intermediate part is less than 50% of an average value thereof.
A silicon carbide single crystal wafer manufactured by a gas growth method, in which:
- a screw dislocation density is 500 dislocations/cm2 or less;
- and
- a difference of the screw dislocation density among a wafer central part, a wafer peripheral part and a wafer intermediate part is less than 50% of an average value thereof.
A method for manufacturing a silicon carbide single crystal ingot, comprising:
- supplying a raw material gas containing hydrogen gas, monosilane, and hydrocarbon gas to a space in which a seed crystal made of silicon carbide is placed;
- and
- growing a silicon carbide single crystal on the seed crystal by keeping a monosilane partial pressure at 4 kPa or more and heating the space to a temperature of 2400° C. to 2700° C., wherein
- in the supplying and the growing, the temperature of the space and supply of the raw material gas are controlled such that a temperature gradient of a growth crystal surface of the silicon carbide single crystal in a radial direction is 0.1° C./mm or less, and a radius of curvature of the growth crystal surface is 4.5 m or more, thereby to produce a silicon carbide single crystal ingot having a growth length of 3 mm or more and an internal stress of 10 MPa or less.
Dependencies are inferred from the claim text.