Characterization of Defects in SiC Substrates and Epilayers

A review will be presented of recent monochromatic and white beam synchrotron topography based studies of defects in SiC substrates, epilayers and devices. The methodologies used in applying these techniques to gain understanding of the origins and evolution of the defect structures in PVT grown boules and CVD grown epilayers will be elucidated. In particular, criteria used in distinguishing grown-in defects from deformation induced defects will be discussed. Contrast observed from the various dislocations present in the crystals will be explained, and it will be shown how contrast simulation can be used to identify the detailed characteristics of the dislocations (for example, both Burgers vector sign and magnitude). Application of the various techniques to the complete analysis of the distribution, character and origins of grown-in c-axis screw dislocations (both hollow and closed-core), deformation induced basal plane dislocations, and grown-in threading edge dislocations will be discussed.