Improving the structural quality and electrical resistance of SrTiO3 thin films on Si (001) via a two-step anneal

We report on the optimization of structural and electrical properties of SrTiO3 thin films grown on Si (001) by hybrid molecular beam epitaxy. Using a dual buffer layer template, 46-nm-thick films grown at high temperatures (850 degrees C) resulted in a layer-by-layer growth mode and a good crystalline quality with rocking curve full width at half maximum (FWHM) of the 002 SrTiO3 peak of nearly 0.6 degrees, which was reduced to 0.4 degrees by increasing the film thickness to 120 nm. A high temperature post-deposition anneal was employed to further reduce the rocking curve FWHM down to 0.2 degrees while preserving a smooth film surface morphology. The low sheet resistance of as-grown and post-growth annealed samples was increased by five orders of magnitude exceeding 10(7) Omega/square using a lower temperature anneal in dry air. This two-step annealing method provides an easy and effective way to improve the crystalline quality of SrTiO3 thin films on Si, providing a path towards the development of electrically insulating, wafer scale virtual perovskite substrates. (C) 2016 AIP Publishing LLC.