Homogeneous Si films on CaF 2/Si(1 1 1) due to boron enhanced solid phase epitaxy

Abstract

The structure and morphology of Si/CaF 2/Si(1 1 1) structures have been investigated by X-ray diffraction (XRD, GIXRD) and X-ray photoelectron spectroscopy (XPS). While CaF 2 films were grown via molecular beam epitaxy (MBE), Si films on CaF 2/Si(1 1 1) are fabricated by surfactant enhanced solid phase epitaxy (SE-SPE). Here Boron was used as a surfactant to obtain semiconductor films of homogeneous thickness. The Si films are entirely relaxed while the CaF 2 films have both pseudomorphic and relaxed crystallites. After exposure to ambient conditions, the Si films have a very thin native oxide film. The homogeneous Si film partially prevents the incorporation of impurities at the interface between the Si substrate and CaF 2 via migration along residual defects of the CaF 2 film.