Low Temperature Epitaxial Silicon Growth in a Rapid Thermal Processor

Abstract

AbstractA rapid thermal processor has been used for the study of epitaxial silicon growth. Without the need for UHV conditions, bulk contamination levels of oxygen and carbon have been reduced to 5E17 cm−3, at a growth temperature of 750°C. In-situ cleans have been assessed as substrate preparation techniques. High temperature H cleans can reduce interfacial doses of both oxygen and carbon to below 5E13 cm−2. I-owever, low temperature cleaning, using a remote fluorine-based plasma, has as yet only achieved oxygen and carbon doses of 5E14 cm−2 and 3E15 cm−2 respectively. Minority carrier lifetimes of a few micro seconds and electron carrier concentrations of about 1E15 cm−3 are typical for undoped films grown at 750°C. In-situ doping with phosphine has also been employed. Typical doping levels of 5E19 cm−3 uniformly distributed throughout the layers have been achieved. The phosphorus is electrically active in the as-grown film with typical carrier mobility estimated to be 104 cm2v−1s−1.