US 12,252,808 B2
Silicon carbide single crystal wafer, and methods for manufacturing silicon carbide single crystal ingot and the silicon carbide single crystal wafer
Isaho Kamata, Tokyo (JP); Hidekazu Tsuchida, Tokyo (JP); Norihiro Hoshino, Tokyo (JP); Yuichiro Tokuda, Kariya (JP); and Takeshi Okamoto, Kariya (JP)
Assigned to DENSO CORPORATION, Kariya (JP)
Filed by DENSO CORPORATION, Kariya (JP)
Filed on Sep. 22, 2020, as Appl. No. 17/027,840.
Claims priority of application No. 2019-173463 (JP), filed on Sep. 24, 2019.
Prior Publication US 2021/0108334 A1, Apr. 15, 2021
Int. Cl. C30B 29/36 (2006.01); C30B 25/00 (2006.01); C30B 25/02 (2006.01); C30B 25/10 (2006.01); C30B 33/00 (2006.01); B32B 3/26 (2006.01)
CPC C30B 29/36 (2013.01) [C30B 25/00 (2013.01); C30B 25/02 (2013.01); C30B 25/10 (2013.01); C30B 33/00 (2013.01); B32B 3/266 (2013.01); Y10T 428/218 (2015.01); Y10T 428/24273 (2015.01); Y10T 428/24298 (2015.01)] 9 Claims
OG exemplary drawing
 
1. A silicon carbide single crystal wafer sliced from a chemical vapor gas grown silicon carbide single crystal ingot, in which:
the silicon carbide single crystal wafer has a diameter with a radius (R) extending from a center (R=0) to an outer peripheral edge (R=R), wherein a wafer central part is located at and/or substantially near the center, a wafer intermediate part is located radially outward from the wafer central part at and/or substantially near a half radius (R=½R), and a wafer peripheral part is located radially outward from both the wafer central part and the wafer intermediate part closest to the outer peripheral edge:
a dislocation density of all dislocations in the wafer, which are indicated by KOH etch pit density or dislocation contrast density evaluated by an X-ray topography measurement, is 3500 dislocations/cm2 or less; and
the wafer central part, wafer intermediate part, wafer peripheral part each comprise a corresponding dislocation density, and a difference of the dislocation density between each pairing of the wafer central part, the wafer intermediate part, and the wafer peripheral part is less than 50% of an average value of the dislocation densities among the wafer central part, the wafer intermediate part, and the wafer peripheral part,
wherein the silicon carbide single crystal wafer contains a metal of 1×1014/cm3 or more in crystal, the metal including at least one of Ta, Ti, and Nb, and
the dislocations including threading screw dislocations, and a threading screw dislocation density is 2000 dislocations/cm2 or less in each of the central part, the intermediate part, and the peripheral part, and is 30% or less of a threading screw dislocation density of each corresponding part of a silicon carbide seed crystal chemical vapor gas grown into the silicon carbide single crystal ingot from which the wafer is sliced.