Thermal stability of ultrathin ZrO2 films prepared by chemical vapor deposition on Si(100)

As a function of thermal treatment, the chemical stability of ultrathin ZrO2 films prepared by chemical vapor deposition on a silicon substrate is investigated by x-ray photoelectron spectroscopy. The chemical structure is stable up to 800 °C in both vacuum and N2 ambient, but a reaction forming zirconium silicide occurs above 900 °C in vacuum. The formation of silicide is accounted for by a reaction mechanism involving a reaction of ZrO2 with SiO, the latter formed above 900 °C at the interface between Si(100) and the thin layer of SiO2 formed during growth of the ZrO2.