We report on the electrical properties of HfO₂ deposited via atomic layer deposition using Hf(NO₃)₄ precursor for metal/oxide/semiconductor gate dielectric applications. Thin films, with less than 1% variation in accumulation capacitance over a 150 mm wafer, have been deposited directly on hydrogen-terminated Si wafers. The effective dielectric constant of thin (<10 nm) films was in the range of κ<sub>eff</sub> = 10–12, the breakdown voltage was about 6–9 MV/cm, and the leakage current was between 3–6 orders of magnitude lower than that of SiO₂. The relative benefit of lower leakage current of HfO₂ over SiO₂ decreased with decreasing effective thickness. Electron trapping was observed under constant voltage stressing.