Monochlorosilane for Low Temperature Silicon Epitaxy

Abstract

Silane (SiH4) and dichlorosilane (DCS) are currently the precursors of choice for the vapor phase epitaxy of silicon at low temperatures (T < 1000 C). Device innovation is pushing down process thermal budgets to the extent that it becomes apparent that in the near future SiH4 and DCS will face challenges in maintaining high growth rates and achieving selectivity at low temperatures. New precursors that produce high growth rates at low deposition temperatures (< 650 C) are needed for advanced epitaxial applications such as recessed source/drain stressors, p-Metal Oxide Semiconductor channel and elevated source/drain structures. In this work, monochlorosilane (MCS) is investigated for the deposition of Si thin films such as blanket Si:P, selective epitaxial Si and Si1-xCx:P. MCS brings a substantial improvement in selective epitaxial silicon growth rate and HCl consumption as compared to DCS.