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 investi gated by transmission electron microscopy (TEM) and high-resolution TE M on cross-sectional preparations. X-ray reflectometry was used for th e determination of the density of the SiC films. These characterizatio ns show that the films are essentially polycrystalline and formed of v ery 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 pro duced by the DIM treatment are analyzed as a consequence of collisiona l effects. The calculations of the damage profile in the growing films indicate that the number of the displacements per target atom (dpa) i s markedly above 1 dpa in the whole film thickness which is in agreeme nt with the prediction of previous models.