GROWTH OF HETEROEPITAXIAL SI1-X-YGEXCY ALLOYS ON SILICON USING NOVEL DEPOSITION CHEMISTRY

We report heteroepitaxial growth of diamond-structured Si1-x-yGexCy alloys on (100)Si substrates. Introduction of C into the diamond lattice is kinetically favored by low-temperature (470 degrees C) interactions of C(SiH3)(4), a novel C-H free carbon precursor, with mixtures of SiH4 and GeH4 using ultrahigh-vacuum chemical vapor deposition techniques. Film thicknesses of 100 to 110 nm with 4-6 at. % C as indicated by Rutherford backscattering carbon resonance spectroscopy were obtained. Cross-sectional transmission electron microscopy and Fourier transform infrared spectroscopy showed crystalline alloy phase formation with no detectable SiC precipitation. Secondary ion mass spectrometry revealed pure and highly homogeneous films. In situ annealing at 675 degrees C resulted in heteroepitaxial films with relatively few defects. (C) 1995 American Institute of Physics.