Ferroelectric Bi4Ti3O12 films on Si(100) with an ultrathin buffer layer ofsilicon oxynitride: A comparative study using X-ray photoelectron spectroscopy

Using pulsed-laser deposition, ferroelectric B4Ti3O12 (BiT) films were grow n on Si(100) with and without an ultrathin buffer layer of silicon oxynitri de (SiON), and the interface states were investigated using X-ray photoelec tron spectroscopy. For both as-grown specimens, the additional oxidation of the interface Si was observed, and their thicknesses were almost identical . Due to the postannealing at 700 degreesC in an oxygen ambient, on the oth er hand, a large difference in the Si oxidation was observed between the tw o specimens. The BiT films on Si(100) without the SiON buffer layer failed in preventing the significant development of the interfacial Si oxidation. On the contrary it was clarified that the 1.3-nm-thick SiON buffer layers s uppressed the additional oxidation to less than 3.5 nm.