Influence of misfit strain on {311} facet development in selective epitaxial growth of Si sub(1-x)Ge sub(x)/Si(100) grown by gas-source molecular beam epitaxy

• Published in: Thin solid films 2000-01, Vol.365 (1), p.147-150
• Main Authors: U'Ren, Greg D, Goorsky, Mark S, Wang, Kang L
• Format: Article
• Language: English
• ISSN: 0040-6090

Selective epitaxy of Si sub(1-x)Ge sub(x)/Si(100) via gas-source molecular beam epitaxy was carried out to compare facet formations in Si sub(1-x)Ge sub(x) to Si. A single {311} facet with a pronounced cusp at the intersection with the (100) surface was observed in large windows (25 mu m). However, facet formations occurring within smaller windows ( less than or equal to 5 mu m) show the development of {311}- and {111}- type facets. For the 1-2 mu m features, no cusps were observed, and facet growth was initiated at an earlier stage of development, avoiding contact with the SiO sub(2) mask. While a 1400 angstroms Si epilayer is expected to have a {311}/{111} ratio of much less than one (approximately 0.15), for the 1-2 mu m windows, however, it is approximately 2. The persistence of the {311}-type facet offers a faster reduction of the original (100) surface that facilitates the fabrication of a nanoscale template.