The surface structures of cleaned or etched 6H-type (00▪1)Si wafers were investigated by using photoemission electron microscopy. In one study, the wafers were exposed to 2 different cleaning processes in order to obtain (v3 x v3)R30º and 3 x 3 reconstructed surfaces. The photoemission electron microscopic images were obtained by using an Hg arc lamp as the photon source, and these revealed that the clean reconstructed surfaces were non-uniform. In a second study, characterization of a H-etched surface by using the photoemission electron microscope, and a free electron laser as the photon source, revealed the presence of a high density of dislocations and a stepped surface structure. The intersections of dislocations with the surface were detected via the etched patterns around them. Reflection high-energy electron diffraction patterns revealed a spotty 3 x 3 image, which was attributed to the presence of excess Si, and a clear (v3 x v3)R30º pattern.

Photo-Emission Electron Microscopy of Cleaned and Etched 6H-SiC (0001). J.D.Hartman, K.Naniwae, C.Petrich, V.Ramachandran, R.M.Feenstra, R.J.Nemanich, R.F.Davis: Materials Science Forum, 2000, 338-342, 353-6