Metal-insulator-metal (MIM) capacitors are fabricated using sputtered HfO2 with Ta and TaN for top and bottom electrodes, respectively. High-capacitance densities from 4.7 to 8.1 fF/mum(2) have been achieved while maintaining the leakage current densities around 1 x 10(-8) A/cm(2) within the normal circuit bias conditions. A guideline for the insulator thickness and its dielectric constant has been obtained by analyzing the tradeoff between the linearity coefficient and the capacitance density.