Structural characterization of SiC films prepared by dynamic ion mixing

Cubic silicon carbide films were grown at 750 degrees C on Si and TA6V substrates using the dynamic ion mixing technique (DIM). A SIC target was sputtered with a 1.2 KeV Ar+ ion beam delivered by a Kaufman-type ion source, and the growing films were simultaneously bombarded with 160 KeV Ar+ ions. The microstructural state of the samples was investigated by transmission electron microscopy (TEM) and high-resolution TEM on cross-sectional preparations. X-ray reflectometry was used for the determination of the density of the SiC films. These characterizations show that the films are essentially polycrystalline and formed of very fine grains of the cubic beta-SiC phase. It is found that the DIM treatment increases the size of the nanocrystallized grains as well as the film density. The crystallisation and densification processes produced by the DIM treatment are analyzed as a consequence of collisional effects. The calculations of the damage profile in the growing films indicate that the number of the displacements per target atom (dpa) is markedly above 1 dpa in the whole film thickness which is in agreement with the prediction of previous models.