Materials selection for SrTiO3-based epitaxial oxide field-effect devices

Abstract

ABSTRACTWe have studied the growth of four wide gap insulator materials, CaHfO3, CaZrO3, NdGaO3, and LaGaO3 on SrTiO3. CaHfO3 was selected as the best material for forming the insulator layer of an all-oxide field-effect device because the films had the best crystallinity on SrTiO3 (100) and the highest breakdown field. (La,Sr)TiO3 was selected as a metallic oxide for fabricating the source and drain electrodes. Metallic layers were obtained by depositing ultrathin amorphous LaTiO3 films at room temperature on SrTiO3 and postannealing at high temperature to promote Sr diffusion from the substrate into the film.