Growth and characterization of ultrathin zirconia dielectrics grown by ultraviolet ozone oxidation

In this letter, we report on the growth of ultrathin films of zirconia on silicon oxide and silicon oxynitride passivated (001) Si by ultraviolet ozone oxidation of Zr metal precursor layers. The oxidation kinetics has been measured using an accelerator-based nuclear reaction analysis. It was found that oxide films up to 55 Å could be grown at room temperature by oxidation at 600 Torr while oxidation at 80 mTorr is self-limiting at 20 Å. The interfaces between the dielectric and the substrate have been characterized by scanning transmission electron microscopy. The ${\mathrm{ZrO}}_{\mathrm{2}}$ films were found to be crystalline as grown. Electrical measurements on capacitor structures with 30-Å-thick ${\mathrm{ZrO}}_{\mathrm{2}}$ films grown on native oxide on silicon show a capacitance–voltage hysteresis of 15 mV and a capacitance-based equivalent oxide thickness of 17 Å at 100 kHz.