EPITAXIAL-GROWTH AND CHARACTERIZATION OF GE1-XCX ALLOYS ON SI(100)

The initial stages (<20 monolayers) of molecular beam epitaxial growth of Ge1-xCx on Si(100) has been studied using both in situ surface ana lytical techniques and ex situ electron microscopy. The Ge1-xCx films studied had nominal C concentrations of 0.2<x<0.8. In situ reflection high-energy electron diffraction indicates crystalline, layer-by-layer growth for room temperature deposition of lower C concentrations (x<0 .4) films and amorphous growth for higher C concentrations. Subsequent high-temperature anneals between 350 and 600 degrees C caused the Ge and C to phase separate, with the Ge forming defective islands while t he C precipitates out of the diamond lattice. Mechanisms leading to th e C concentration-dependent island morphologies are suggested. (C) 199 5 American Institute of Physics.