KINETICS OF NUCLEATION AND GROWTH OF SI ON SIO2 IN VERY LOW-PRESSURE SIH4 CHEMICAL VAPOR-DEPOSITION

The initial growth kinetics for SiH4 chemical vapor deposition of Si on SiO2 at low temperature (500-600-degrees-C) have been revealed using rapid thermal UHV-CVD, together with in situ H-2 thermal desorption spectroscopy to titrate the amount of exposed Si surface. In the few mTorr pressure range, the reaction is heterogeneous, i.e., dominated by surface reaction. Below approximately 0.7 monolayer Si coverage, the growth kinetics is rapid (approximately t4), indicating spontaneous generation of new nuclei, while at higher coverage Si island growth dominates.