Growth of Selective Silicon Epitaxy Using Disilane and Chlorine on Heavily Implanted Substrates: I. Role of Implanted  BF 2

Abstract

In this report, we present results on the low thermal budget deposition of selective silicon epitaxy on heavily BF 2 implanted substrates using Si 2 H 6 and Cl 2 in an ultrahigh vacuum rapid thermal chemical vapor deposition reactor. Si growth kinetics, selectivity to SiO 2 , dopant incorporation, and epitaxial quality have been investigated for varying implant dose conditions and varying levels of chlorine during processing. Contrary to published reports, no significant selectivity degradation mechanism has been observed for oxides implanted, and therefore, damaged by BF 2 ions. Additionally, with heavily implanted boron substrates no reduction in silicon growth occurred despite the presence of a hydrophilic substrate surface just prior to epitaxial growth. Although the hydrophilic surface did not affect the silicon growth 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 microscopy. The incorporation of boron into the deposited epitaxial films has been investigated and abrupt profiles or intentionally diffuse structures were achieved through variation of the process sequence and annealing conditions.