Detailed characterization using x-ray diffractometry, scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and Auger infrared and focused ion-beam spectroscopy, was carried out on cubic SiC films grown on single-crystal (100) Si substrates by reactive hydrogen plasma sputtering over a range of growth temperatures between 700 and 1000 °C. It was found that the first few deposited atomic layers were always amorphous. The subsequent SiC films showed well-defined (111) growth at the lowest temperatures, becoming randomly oriented by 1000 °C. The measured C:Si ratio was always >1, and varied with depth inside a film and also with temperature. At higher temperatures, the presence of “hollow voids” was observed, our data being consistent with their formation by outdiffusion of Si atoms from the substrate through the SiC layer. Associated with the hollow voids we observed the presence of a porous, highly C-rich region at the Si–SiC interface. We propose that this was due to diffusion of C from the SiC film into the voids themselves. ©1997 American Institute of Physics.