Composition dependence of band alignment and dielectric constant for Hf1−xTixO2 thin films on Si (100)

Composition-dependent band alignment and dielectric constant for Hf1−xTixO2 thin films on Si (100) have been investigated. It was found with increasing Ti content, the band gap and band offsets (ΔEv and ΔEc) of Hf1−xTixO2 films against Si all decrease and the optimal Ti content in the films should be no higher than 21%, at which ΔEc is 1.06 eV. The dielectric constant of the films not only can increase up to 31.3, but show a linear increase with increasing TiO2 content. Compared with HfO2 thin film with similar equivalent oxide thickness, low leakage currents were obtained.