Epitaxial growth of CaxCd1-xF2 mixed crystal films on Si substrates

Mixed crystal films of CaxCd1-xF2 were epitaxially grown on Si(111) substra tes covered with a thin CaF2 buffer layer. Using the molecular-beam epitaxy method, 110-nm-thick mixed crystal films were grown at 200 degreesC on 10- nm-thick CaF2 buffer layers on Si(111). Rutherford backscattering spectrosc opy revealed that the composition of the mixed crystal layer, x, was consis tent with the Bur ratio of a CaF2 molecular beam and a CdF2 molecular beam, and that channeling minimum yields of less than 20% were obtained for the entire range of composition (x = 0 to x = 1). Very smooth surface morpholog y with 0.29 nm of rms was obtained for the x = 0.31 layer, compared to thos e of pure CaF2 or CdF2 layers grown at the same growth temperature.