3-DIMENSIONAL STUDIES OF SIC POLYTYPE TRANSFORMATIONS

Scanning electron microscopy technique in colour cathodoluminescence m ode is proposed for two-dimensional (2-D) and three-dimensional (3-D) studies of polytype structures of SiC epitaxial layers grown by the su blimation sandwich method. It allows us to perform layer-by-layer stru cture analysis of a polytype on depths up to 2.5 mu m with high resolu tion. An effect of polytype instability under growth on singular subst rate (0001) is revealed. It leads to the fact that the grown SiC layer represents the set of alternating sublayers of different polytypes su ch as 4H, 6H, and 3C. Some mechanisms of polytype syntaxy in SiC are d iscussed.