Low-temperature Si and Si:Ge epitaxy by uitrahigh-vacuum/ chemical vapor deposition: Process fundamentals

This paper is an overview of work at the IBM Thomas J. Watson Research Center on the chemical and physical considerations underlying the development of a lowtemperature chemical vapor deposition process, designated ultrahigh-vacuum/ chemical vapor deposition (UHV/CVD). The origins of the rigorous vacuum and chemical purity requirements of the process are discussed. Operating in the range of 500°C, the process has made it possible to explore the use, in silicon-based devices and atomiclength-scale structures, of a number of metastable materials in the Si:Ge system. Also discussed is associated experimental work on the fabrication of high-speed heterojunction bipolar transistors and highmobility two-dimensional hole-gas structures. © 2000 IBM.