High-Density and Low-Leakage-Current MIM Capacitor Using Stacked $\hbox{TiO}_{2}/\hbox{ZrO}_{2}$ Insulators

We have fabricated high-kappa Ni/TiO2/ZrO2/TiN metal-insulator-metal (MIM) capacitors. A low leakage current of 8 times 10-8 A/cm2 at 125degC was obtained with a high 38- fF/mum2 capacitance density and better than the ZrO2 MIM capacitors. The excellent device performance is due to the lower electric field in 9.5-nm-thick TiO2/ZrO2 devices to decrease the leakage current and to a higher kappa value of 58 for TiO2 as compared with that of ZrO2 to preserve the high capacitance density.