Low temperature growth of Si:Ce thin films with high crystallinity and uniform distribution of Ce grown by solid-source molecular beam epitaxy

Abstract

Diluted magnetic semiconductor (DMS), Si:Ce thin films with the Ce concentration below 0.3 at%, are prepared on (0 0 1) Si substrates by low-temperature molecular beam epitaxy (LT-MBE) method. Since a smooth surface is obtained by optimizing the surface-cleaning processes of Si substrate and the deposition conditions of buffer layer, Si:Ce thin films are able to be grown at the growth temperature of 450 °C. RHEED oscillations are observed at the initial stage of the growth, indicating two-dimensional growth. The LT growth enables to obtaining uniform distribution of Ce in Si without hillock or pit formation. The X-ray diffraction (XRD) patterns reveal that all the films are grown epitaxially on the (0 0 1) Si substrate and no extra diffractions corresponding to the silicide are recognized.