A diffraction approach for the study of the mechanism of 3C to 6H transformation in SiC

Abstract

Diffraction patterns taken from cubic silicon carbide crystals partially transformed to a 6H (ABCACB, ...) structure show the presence of characteristic diffuse streaks parallel tobic suggesting that the transformation takes place by statistical insertion of stacking faults. Theory of diffraction for cubic crystals undergoing transformation to the 6H structure by non-random insertion of deformation and layer displacement faults is developed separately. It is shown that a choice between the two routes of transformation can be made by comparing the theoretically predicted diffraction effects with those experimentally observed. Using such a diffraction approach, it is concluded that the transformation takes place by a non-random insertion of layer displacement faults. It is also shown that the observed diffraction characteristics cannot be explained in terms of non-random twinning through growth faults.