INFLUENCE OF TEMPERATURE ON THE STRUCTURE OF SIC COATINGS PREPARED BYDYNAMIC ION MIXING

We deposited silicon carbide films, 0.5 mu m and 0.86 mu m thick at ro om temperature (RT) and 750 degrees C on (100) silicon wafers and TA6V substrates. An SiC target was sputtered with a 1.2 keV Ar+ ion beam d elivered by a Kaufman-type ion source, and the growing films were cont inuously bombarded with a beam of 160 keV Ar+ ions. The microstructura l state of the films was investigated by complementary techniques: tra nsmission electron microscopy (TEM), high-resolution TEM, glancing X-r ay diffraction (GXRD) and Fourier transform infrared spectroscopy (FTI R). All these characterization methods show that the bombardment of th e growing films induces important structural changes. The SiC films pr epared at RT without mixing are amorphous, whereas those deposited by dynamic ion mixing (DIM) at RT exhibit the beginning of crystallizatio n of the beta-SiCphase. At 750 degrees C the films prepared by DIM are formed of nanocrystallized grains of the cubic beta-SiC phase.