GROWTH OF STRAINED SI SI1-YCY/SI1-XGEX STRUCTURES BY MBE/

Carbon doping during Si molecular beam epitaxy (IMBE) has been studied with C obtained by sublimation of SiC in a high-temperature cell. Acc umulation of surface roughness has been observed, which can lead to re duction of C-induced strain. This surface roughening is reduced at hig h growth rates and/or low substrate temperatures. Modulation of the gr owth temperature during the growth sequence has been used to prepare S i1-yCy/Si multiple quantum well (MOW) structures with optimized photol uminescence and X-ray diffraction (XRD) properties. Preparation of Si1 -yCy/Si1-xGex MQW structures is reported and during growth at 430 degr ees C formation of Ge-rich precipitates occurs, while growth at 370 de grees C leads to very abrupt interfaces. (C) 1998 Elsevier Science Ltd . All rights reserved.