THE ANNEALING EFFECT OF CRYSTAL 4H-SIC FILMS PREPARED BY PULSED-LASERDEPOSITION

SiC films were prepared by pulsed XeCl laser ablation of ceramic SIC t arget on Si(100) substrate at temperature 850 degrees C and post-depos ition high temperature annealing above 1100 degrees C (1100 degrees C< T < 1400 degrees C) in high vacuum (1.3x10(-7) Pa). The surface morph ology, crystal structure, composition and chemical state of the elemen t in the films before and after annealing were studied by X-ray diffra ction, transmission electron microscopy, scanning electron microscopy, Auger electron Spectrum, X-ray photoelectron spectrum and photolumine scence methods. It was found that the films were consisted of polycrys tal 4H-SiC structure before annealing and were turned into singlecryst al epitaxial 4H-SiC after annealing. The surfaces of the films were sm ooth and the adhesion of films with the substrate was good. The films were transparent. Excited by the laser with wavelength 290 nm at room temperature, the films emitted two luminescence bands with the peaks a t 377 nm and 560 nm. The emission at 377 nm was attributed to the comb ination of the transmission among the valence and conductor bands, whi le the one at 560 nm was possibly to be from exciton emission.