Fundamental equilibrium considerations derived from the Si/H2O/O2/SiO2 system have been successfully employed in the design and operation of a novel low temperature epitaxial silicon process. Films have been deposited in the range 750° < T < 850°C, with all resulting material epitaxial. TEM studies showed the transition to high quality, low defect density material to occur between 750° and 800°C, and such films were found to be of high chemical purity as well. In addition, UHV/CVD is shown to be a high throughput multiwafer system, achieving good film uniformities in a high wafer packing density environment, attributable to operation in the low pressure limit of chemical kinetics. © 1986, The Electrochemical Society, Inc. All rights reserved.