Formation of metal disilicide layers contacting ion beam-synthesized, buried 3C-SiC layers in silicon

Large-area heteroepitaxial Si/SiC/Si structures can be formed by ion beam synthesis. In this paper, the conversion of the Si top layer of such structures into a metal disilicide contact layer by high-dose titanium ion implantation is described. Rutherford backscattering spectroscopy, cross-sectional transmission electron microscopy, energy-filtered transmission electron microscopy, electron diffraction, X-ray diffraction, scanning electron microscopy, atomic force microscopy, and electrical measurements are used to characterize the resulting layer systems. It is shown that by proper adjustment of the ion dose-taking into account the sputtering rates of Si and Ti atoms-well-conductive textured C54-TiSi2 contact layers can be formed in a single fabrication step. These layers are structurally and electrically stable up to 900 degreesC or higher. The surface roughness is determined by the grain size of the formed silicide and can be controlled via the implantation temperature. It is shown that at overly high doses, metal-rich silicides are formed. In this case, Si diffusion from the substrate to the metallization layer via strain-induced macrodefects in the SIC thin film leads to cavity formation at the lower SiC/Si interface. (C) 2001 Elsevier Science B.V. All rights reserved.