Characterization of Si1−xGex epilayers grown using a commercially available ultrahigh vacuum chemical vapor deposition reactor

Abstract

Si1−xGex epitaxial layers were grown at T=525 °C using a commercially available, ultrahigh vacuum chemical vapor deposition reactor. Various techniques, including cross-sectional transmission electron microscopy, Auger electron spectroscopy, secondary ion mass spectroscopy, double crystal x-ray diffraction, and photoluminescence (PL) are used to characterize this material. For the first time, phonon resolved PL is used to map out the composition uniformity obtained with this high throughput, production-ready technology. The composition variations along most of the wafer surface (except the flats) do not exceed ±0.15%. A discussion follows on the limitations of this technology, including the critical thickness for misfit strain relaxation, compared to other growth techniques such as molecular beam epitaxy and rapid thermal chemical vapor deposition. The material grown here exhibits characteristics that are very encouraging for the prospect of manufacturing high frequency devices and circuits.