Observation of the formation processes of hollow voids at the interface between SiC film and Si substrate

The formation processes of hollow voids which appear at the interface of cubic SiC film/Si substrate are observed using scanning and transmission electron microscopy. The cubic SIC films are prepared on a (100) Si substrate which is kept at a temperature ranging from 700 degrees C to 1000 degrees C by means of reactive hydrogen plasma sputtering of a ceramic SiC target. We found that the hollow voids are first formed at lattice defects near the Si substrate surface due to the high reactivity of the defects, and are later formed at reaction zones which form by the film growth nuclei with the Si substrate surface. Formation and growth of the hollow voids are complex processes that depend on conditions such as substrate temperature, areal density of both the lattice defects and the film growth nuclei at the Si substrate surface; and diffusion rate of gas atoms through the growing film.