Growth mechanism difference of sputtered HfO₂ on Ge and on Si

Difference in growth mechanism of HfO₂ on Ge and Si deposited by the reactive sputtering was analyzed. It was found that the interface layer and the HfO₂ film was thinner on Ge than that on Si. An advantage of HfO₂/Ge was found over HfO₂/Si systems from the viewpoint of further reduction of the gate oxide thickness in the ultrathin high-k gate dielectric region. The results show that the metallic Hf layer, deposited before HfO₂ deposition have a crucial role for the thickness differences of both interface layers and HfO₂ films on those substrates.