Metal-insulator-metal (MIM) capacitors with high-k HfO 2 dielectrics were fabricated and investigated. Experimental results show low leakage current densities of ∼5 × 10 -9 A/cm 2 and high capacitance density of ∼3.4 fF/μm 2 at 100 kHz in the MIM capacitors. The temperature coefficient and frequency dispersion effect for these MIM capacitors were very small. Different metal electrodes like tantalum, aluminum and copper were also investigated and compared. Finally, the mechanism of electrical transport was extracted for the HfO 2 MIM capacitors to be Poole-Frenkel-type conduction mechanism.