Epitaxial growth on silicon and characterization of MnF2 and ZnF2 layers with metastable orthorhombic structure -: art. no. 013519

The growth of MnF2 and ZnF2, layers on Si(001) and Si(111) substrates was studied by molecular-beam epitaxy. Calcium fluoride buffer layers with (001), (110), and (111) orientations were used to prevent chemical interaction of MnF2 and ZnF2 molecules with the Si substrate. The analysis of x-ray and reflection high-energy electron-diffraction (RHEED) patterns showed that MnF2 layers grow on all of these planes in the orthorhombic alpha-PbO2-type crystal phase observed earlier only at high pressures and temperatures. Atomic force microscopy revealed a strong dependence of the surface morphology on the buffer orientation and growth temperature. The best-ordered MnF2 growth occurred at 500 degrees C on a CaF, (110) buffer layer. The diffraction analysis enabled us to find the epitaxial relations at the MnF2/CaF2 interface. A careful analysis of the RHEED patterns of the films grown on CaF2(001) showed a similarity in the structure and growth modes between MnF2 and ZnF2 layers, with ZnF2, tending to form multiphase layers. These findings are in agreement with the x-ray diffraction measurements. 0 2005 American Institute of Physics.