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 O-2, this interfacial reaction is suppressed, and a metal-insulator-semiconductor capacitance equivalent to 0.5 nm of SiO2 is obtained for a 10 unit cell SrTiO3/1 unit cell (Ba,Sr)O/p-Si(100) stack. (C) 2006 American Institute of Physics.