Heteroepitaxial growth of 3C-SiC on (100) silicon by C 60 and Si molecular beam epitaxy

Abstract

Thin, hydrogen-free 3C-SiC films were grown on (001) silicon substrates at rather low temperatures by C 60-carbonization under simultaneous silicon co-deposition at different rates. Fullerene molecules and silicon were evaporated from Knudsen cells. The dependence of the structure and phase composition on Si rate and working pressure has been examined. Optimum growth conditions for the resulting SiC films are examined. Elastic recoil detection analysis spectra show the formation of a stoichiometric SiC layer under all conditions applied. X-Ray diffraction measurements reveal that the resulting 3C-SiC films, obtained under optimized conditions, are free of twin structures and epitaxially aligned to the underlying silicon substrate. Cross-section transmission electron microscopy confirms a significant structural improvement as Si is co-deposited. For samples formed without Si co-deposition, pits of pyramidal shape were found in the silicon substrate near the SiC/Si interface by scanning electron microscopy. Silicon co-evaporation during carbonization leads to a significant reduction of the pit size.