Epitaxial thin films of MgO on Si using metalorganic molecular beam epitaxy

Abstract

Epitaxial cubic MgO thin films have been deposited on single crystal Si(001) substrates by metalorganic molecular beam epitaxy. The Mg source was the solid precursor magnesium acetylacetonate and a rf excited oxygen plasma was the oxidant. The growth process involved initial formation of an epitaxial β-SiC interlayer followed by direct deposition of a MgO overlayer. The films were characterized by in situ reflection high energy electron diffraction, x-ray diffraction, conventional and high resolution transmission electron microscopy, atomic force microscopy, Auger electron spectroscopy, and Fourier transform infrared spectroscopy. The β-SiC interlayer had an epitaxial relationship such that SiC(001)∥Si(001) and SiC [110]∥Si [110]. The SiC interlayer showed a columnar grain structure with planar defects including twin bands and stacking faults. The MgO overlayer showed an epitaxial relationship given by MgO(001)∥Si(001) and MgO[110]∥Si[110]. No evidence of twins in the MgO layers was observed.