SELECTIVE GERMANIUM EPITAXIAL-GROWTH ON SILICON USING CVD TECHNOLOGY WITH ULTRA-PURE GASES

Low pressure chemical vapor deposition (LPCVD) experiments of Ge are presented. The results show that Ge epitaxy is possible by the LPCVD technique at low temperatures, if high-purity reactive gases and ultrahigh vacuum (UHV) compatible CVD equipment is used. Epitaxial films can be grown for several deposition parameter combinations. At low GeH4 pressures facet formation can be observed, which originates from a stepflow dominated growth mechanism. At higher partial pressures plain surfaces are obtained due to dangling bond dependent growth, which is verified in a comparison between several Si substrate orientations. Ge CVD reveals perfect Si/SiO2 selectivity and can, therefore, be used as a contact hole filling method as shown by Ge plugs in contact holes. © 1990.