The surface and interface reaction of metal thin film on sapphire substrate

The microscopic properties of the surface and interface reaction between active metals such as Ti, Zr and sapphire substrate have been studied using X-ray photoelectron spectroscopy (XPS). XPS results indicate that the submonolayer of titanium does not react with oxygen into sapphire at room temperature, but at about 1073 K titanium reduces the sapphire with the formation of TiO2 and metallic Al at the interface. But in the case of Zr, there is no tendency of any reaction at the interface with sapphire substrate even at high temperature. The result shows that Ti reacts more actively with sapphire than Zr does.