High-Performance Metal-Insulator-Metal Capacitors With HfTiO/Y2O3 Stacked Dielectric

The HfTiO/Y2O3 stacked dielectric is proposed as the dielectric of metal-insulator-metal (MIM) capacitor. Y2O3 is more thermodynamically stable than HfTiO as contacting with TaN electrode. Interfacial layer thickness and leakage current density can be reduced by inserting a thin Y2O3 layer between HfTiO and TaN. The negative quadruple voltage coefficient of capacitance (VCC-alpha) of Y2O3 cancels out the positive VCC-alpha of HfTiO to achieve low VCC-alpha. The MIM capacitor structure with HfTiO/Y2O3 dielectric shows a capacitance density that is higher than 11 fF/mu m(2) and VCC-alpha that is lower than 1222 ppm/V-2. The leakage currents at -1 and -2 V are 6.4 and 14 nA/cm(2), respectively. These results suggest that the HfTiO/Y2O3 stacked dielectric is a promising candidate for MIM capacitors.