Influences of pressure and substrate temperature on epitaxial growth of gamma-Mg2SiO4 thin films on Si substrates

摘要

An epitaxial-Mg2SiO4 thin film can be a good buff. er between the Si substrate and some oxide thin filmsfor 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 gamma- 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 degrees C and the pressure changing from 10Pa to 15Pa, in the XRD spectra the gamma-Mg2SiO4 (400) peak grows drastically while the MgO (200) peak is suppressed. Keeping the pressure at 15 Pa and increasing the temperature from 500 degrees C to 570 degrees C further can improve thefilm epitaxy, while working at 780 degrees C and 11 Pa seems to give very good results. X- ray photoelectronic spectroscopy and phi scan are used to characterize the stoichiometry, crystallinity, and in- plane growth of the samples.