Solid phase epitaxy of SrTiO3 on (Ba,Sr)O∕Si(100): The relationship between oxygen stoichiometry and interface stability

Abstract

Key aspects of the growth process of epitaxial SrTiO3 with crystalline interface on silicon are outlined. An important step in this process is the solid phase epitaxy in ultrahigh vacuum of amorphous SrTiO3 on top of a few monolayer thick, low-temperature grown, epitaxial (Ba,Sr)O∕Si(100) template. Insufficient oxygen supply during the SrTiO3 deposition step causes the formation of amorphous alkaline-earth silicates and TiSix at the Si∕epitaxial oxide interface during ultrahigh vacuum annealing. Performing SrTiO3 deposition in excess O2, this interfacial reaction is suppressed, and a metal-insulator-semiconductor capacitance equivalent to 0.5nm of SiO2 is obtained for a 10unit cell SrTiO3∕1unit cell (Ba,Sr)O∕p-Si(100) stack.