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

Abstract

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 low-temperature 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 atomic-length-scale structures, of a number of metastable materials in the Si:Ge:B system. Also discussed is associated experimental work on the fabrication of high-speed heterojunction bipolar transistors and high-mobility two-dimensional hole-gas structures.