Structural defects in 4H and 6H SiC wafers have been studied by means
of synchrotron X-ray topography and optical microscopy. The effect of
seed crystal attachment, orientation, growth face shape, reloading and
continued growth are discussed. A comparison between 4H and 6H materi
al is made also. The results relate the origin oi. different defects t
o the mentioned growth conditions. (C) 1997 Elsevier Science S,A.