Structural defects in SiC ingots investigated by synchrotron diffraction imaging

4H silicon carbide as-grown ingots were investigated by diffraction imaging using synchrotron radiation. The white beam section topographs obtained fo r various sample geometries allowed us to reveal structural imperfections b efore slicing the bulky ingots to the thin wafers used as electronic device substrates. The systematic investigation indicated that the observed inclu sions of different polytypes in 4H-SiC ingots are correlated with the 8 deg rees off-axis orientation of the seed. These inclusions, formed at the begi nning of the crystal growth, provoke planar defects that propagate along th e main vertical axis of the cylindrical crystal. New findings permitted us to understand the inclusion formation with the aim to increase the useful v olume.