EPITAXIAL-GROWTH OF CAF2 SI CAF2 ON SI(111)

High quality CaF2/Si/CaF2/Si(111) structures have been grown epitaxial ly by molecular beam epitaxy and characterized by X-ray diffraction an alysis, Rutherford backscattering spectroscopy and transmission electr on microscopy. High crystalline quality CaF2 layers are achieved when the thickness of the middle Si layer is small. The films degrade if th e thickness of the Si layer exceeds 10 nm. The epitaxial orientations of the two CaF2 layers can be identical or azimuthally rotated 180 deg rees with respect to each other, depending on how the middle Si film i s deposited.