MICROPIPE DEFECTS AND VOIDS AT BETA-SIC SI(100) INTERFACES/

The application of an uncommon silicon substrate pretreatment and a ca rbonization procedure without temperature ramp in a CVD reactor was fo und to create a new kind of defect besides the usual voids at beta-SiC /Si(100) interfaces. SiC-covered micropipes of minute size and of high area densities evolve into the substrate by Si outdiffusion and simul taneous ingrowth of SiC. Results of our systematic investigations of m icropipes and voids, obtained mainly by transmission electron microsco py (TEM), are summarized. The micropipe formation is obviously determi ned by very specific conditions such as, e.g., a high density of SiC n uclei at high carbonization temperatures. Recent new results demonstra te that micropipes together with voids can also develop in carbonizati on experiments during a relatively slow temperature rise at very low h ydrocarbon concentrations. (C) 1997 Elsevier Science S.A.