The photoelastic constant and internal stress around micropipe defects of 6H-SiC single crystal

Hexagonal silicon carbide (6H-SiC) single crystals made by a modified Lely method contain a ‘micropipe’ which is one kind of serious defects degrading device performance. The micropipe accompanies strong internal stress around itself. We determined the photoelastic constant in the plane of (00·1) 6H-SiC and then estimated the magnitude of the internal stress around the micropipes. The photoelastic constant was 2.73 brewster at λ=546 nm. The internal stress around the micropipe was estimated to be 113∼166 MPa.