Influences of Pressure and Substrate Temperature on Epitaxial Growth of γ-Mg₂SiO₄ Thin Films on Si Substrates

An epitaxial γ-Mg₂SiO₄ thin film can be a good buffer between the Si ubstrate and some oxide thin films. For high temperature superconducting multilayer structures, hopefully it can be taken as an insulating layer to
replace the widely used MgO film. To explore such possibilities, we carry out systematic studies on the influences of pressure and substrate temperature on the epitaxy of γ-Mg₂SiO₄ thin films grown on Si (100) substrates using rf magnetron sputtering with an Mg target of purity of 99.95 percent. With the
substrate temperature kept at 500°C and the pressure changing from 10Pa to 15Pa, in the XRD spectra the γ-Mg₂SiO₄ (₄₀₀) peak grows drastically while the MgO (200) peak is suppressed. Keeping the pressure at 15Pa and
increasing the temperature from 500°C to 570°C further can improve the film epitaxy, while working at 780°C and 11Pa seems to give very good
results. X-ray photoelectronic spectroscopy and Ф scan are used to characterize the stoichiometry, crystallinity, and in-plane growth of the samples.