Epitaxial growth of laminar crystalline silicon on CaF2

Si heteroepitaxy on CaF2 was studied with x-ray photoelectron spectroscopy and diffraction and low-energy electron diffraction to determine the interface bonding and silicon overlayer growth mode. The CaF2 surface was prepared by irradiation with low-energy electrons and exposure to arsenic, which replaced surface fluorine atoms with arsenic. Thin Si films (1.3 nm) were subsequently deposited at 550 °C. The Si films completely cover the CaF2 substrate and have a type-B orientation. The resultant interface has Si–Ca bonds, with the As surfactant layer terminating the Si surface in a 1×1 structure.