Growth of selective silicon epitaxy using disilane and chlorine on heavilyimplanted substrates - I. Role of implanted BF2

In this report, we present results on the low thermal budget deposition of selective silicon epitaxy on heavily BF2 implanted substrates using Si2H6 a nd Cl-2 in an ultrahigh vacuum rapid thermal chemical vapor deposition reac tor. Si growth kinetics, selectivity to SiO2, dopant incorporation; and epi taxial quality have been investigated for varying implant dose conditions a nd varying levels of chlorine during processing. Contrary to published repo rts, no significant selectivity degradation mechanism has been observed for oxides implanted, and therefore, damaged by BF2 ions. Additionally, with h eavily implanted boron substrates no reduction in silicon growth occurred d espite the presence of a hydrophilic substrate surface just prior to epitax ial growth. Although the hydrophilic surface did not affect the silicon gro wth rate, the epitaxial defect density did increase with increasing implant dose and chlorine flow rate during processing. The nature of these defects has been studied using atomic force microscopy and transmission electron m icroscopy. The incorporation of boron into the deposited epitaxial films ha s been investigated and abrupt profiles or intentionally diffuse structures were achieved through variation of the process sequence and annealing cond itions. (C) 1999 The Electrochemical Society. S0013-4651(98)08-056-2. All r ights reserved.