SURFACE POLARITY DEPENDENCE IN STEP-CONTROLLED EPITAXY - PROGRESS IN SIC EPITAXY

The dependence of surface polarity in step-controlled epitaxy of 6H- a nd 4H-SiC polytypes on off-oriented {0001} substrates was examined. Do minant step heights correspond to half (6H-) or a full (4H-) unit cell s of the SiC polytypes. The background doping level can be reduced to legs than 1x10(14) per cm(3) by growth under C-rich conditions. High e lectron mobilities of 431 cm(2) Vs(-1) for 6H-SiC and 851 cm(2) Vs(-1) for 4H-SiC were obtained. The high quality of the epilayers was also elucidated, since the deep trap concentration detected by deep level a nalysis was in the order of 10(12) per cm(3). The surface polarity dep endence and polytype dependence of impurity doping were demonstrated. (C) 1997 Elsevier Science S.A.