Thermal treatment effects on interfacial layer formation between ZrO2 thin films and Si substrates

This paper describes the growth condition of stoichiometric ZrO2 thin films on Si substrates and the interfacial structure of ZrO2 and Si substrates. The ZrO2 thin films were prepared by rf-magnetron sputtering from Zr target with mixed gas of O2 and Ar at room temperature followed by post-annealing in O2 ambient. The stoichiometric ZrO2 thin films with smooth surface were grown at high oxygen partial pressure. The thick Zr-free SiO2 layer was formed with both Zr silicide and Zr silicate at the interface between ZrO2 and Si substrate during the post-annealing process due to rapid diffusion of oxygen atoms through the ZrO2 thin films. After post annealing at 650-750 °C, the multi-interfacial layer shows small leakage current of less than 10−8 A/cm2 that is corresponding to the high-temperature processed thermal oxidized SiO2.