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

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.