Highly oriented diamond growth on SixGe1-x (100) thin films

Abstract

Highly oriented (100) diamond films have been successfully grown on SixGe1-x(100) thin films by bias enhanced nucleation (BEN) in microwave plasma chemical vapor deposition (MPCVD) system. Raman spectra show the 1332 cm(-1) peak which proves the formation of diamond. Diamond nucleation density on SixGe1-x substrate estimated by scanning electron microscopy is higher than 10(9) cm(-2). The interface between diamond and SixGe1-x substrate was characterized by transmission electron microscopy (TEM). About 20 nm decrease in thickness of the SixGe1-x film. was observed after bias enhanced nucleation step. TEM shows the existence of silicon carbide and heteroepitaxial diamond grains grown on SixGe1-x substrate. Characterization from high-resolution TEM on the specimen of short time deposition reveals that a number of epitaxial diamond grains were directly nucleated on SixGe1-x with {111} interplanar spacing ratio of diamond and SixGe1-x of 2:3. The diamond nucleation is found to be preferred on the ridge position of the rough substrate surface. Diamond {100} facets were quickly developed in the early stage of growth. (C) 2004 Elsevier B.V. All rights reserved.