Growth of crystalline quality SiC on thin and thick silicon-on-insulator structures

We have grown silicon carbide (SiC) on ultrathin Si (about 300 angstroms) and on thick Si (about 2000 angstroms) on commercial SIMOX (from IBIS Corp and SOITEC, Inc.), and bulk Si. Electron diffraction and Rutherford backscattering spectroscopy (RBS)/channeling studies indicate epitaxial growth of single-crystal β-SiC even at growth temperatures as low as 1100 °C. We have already demonstrated the fabrication of ultrathin Si, as thin as 140 angstroms on SiO₂ by using the low-energy SIMOX (LES) (20 to 30 keV) process to produce films of lower cost and excellent integrity compared to thinned commercial SIMOX. Based on these results, ultrathin Si-on-insulator (SOI) substrates appear to have great potential for device quality SiC films. However, the carbonization and/or growth of SiC on ultrathin Si requires further optimization because the processes for surface cleaning and growth of SiC on bulk Si substrates cannot be applied because of the thinness of the substrate layers. Additional carbonization work at higher temperatures has indicated the possibility of converting the entire Si top layer.