HfO 2 thin films were atomic-layer deposited using different-precursor partial pressures and at different growth temperatures on n-and p-type silicon substrates. The effect of processing parameters and film thickness on the electrical quality of the oxide–semiconductor interface was studied. Deep-level-transient spectroscopy and conductance-transient techniques revealed 3–10× 10 11 cm− 2 eV− 1 interface trap densities, somewhat dependent on the processing conditions. Charge trapping took place mainly between the semiconductor and defects located at energies close to the majority-carrier-semiconductor-band edge.