Epitaxial Silicon-Carbon Alloy Growth by Laser Induced Melting and Solidification

Abstract

ABSTRACTIon implantation of carbon into single-crystal silicon followed by excimer laser irradiation was used to create supersaturated, epitaxial SixC1-x. films. Crystallization proceeded from the underlying single-crystal silicon through the carbon containing layers at velocities of approximately 5 m/s. Characterization by high-resolution x-ray diffraction and Fourier-transform infrared absorption indicate that the carbon is found predominantly on substi-tutional lattice sites for concentrations up to 1.4 at.% C. Secondary-ion mass spectrometry profiles and numerical mass transfer calculations were used to estimate the diffusion coefficient of carbon in the liquid as 2-3 × 10−4cm2/s with a segregation coefficient greater than 0.4. Unusual diffusion behavior was observed for the carbon at 1.4 at.% C. At higher concentrations, evidence of SiC precipitates was observed in transmission electron microscope images and FTIR absorption spectra.