Epitaxial Mg2SiO4 thin films with a spinel structure grown on Si substrates

With a Mg target of purity of 99.95%, epitaxial Mg2 SiO4 thin films are grown on Si (1 0 0) substrates using RF magnetron sputtering at relatively high pressure (6–13 Pa) and high substrate temperature (700–780 °C). These Mg2SiO4 thin films are formed in a spinel structure with a lattice constant of 8.10 Å, and are cubic with four-fold symmetry. The spectra of X-ray photoelectronic spectroscopy (XPS) give a stoichiometric ratio of Mg:Si:O=1.8:1:4Mg:Si:O=1.8:1:4. The growth rate of thin film decreases as the growth time increases, the film thicknesses are 70 nm for a deposition time of 30 min, 120 nm for 1 h, and 160 nm for 2 h, respectively. Over an area of 5μm×5μm, the root mean square (rms) roughness of Mg2SiO4 thin film is 11 nm. Such films can be of practical values in integrated circuits as buffer layers, etc. The details of the fabrication and characterization of these samples are discussed here.