Wafers (5cm) of 6H-type material were studied. Examination of the wafers under crossed polarisers revealed black and white stripes which corresponded to sub-grain boundaries. The creation of the stripes was affected by thermal expansion and the shape of the bulk surface. The phenomenon was confirmed by X-ray diffraction examination. In this way, 2 areas were identified within which sub-grain boundaries were easily created.

Characterisation of 2-Inch SiC Wafers Made by the Sublimation Method. M.Sasaki, H.Shiomi, S.Nishino: Materials Science Forum, 2001, 353-356, 267-70