Hafnium oxide-aluminum oxide (HfAlO) dielectric films were cosputtered using HfO2 and Al2O3 targets, and their properties are studied in comparison with pure HfO2 films. The X-ray diffraction studies confirmed that the HfO2 films are nanocrystalline with a monoclinic phase. The as-deposited HfAlO films with a chemical composition of (HfO2)(0.86)(Al2O3)(0.14) are amorphous even after annealing at 500 degrees C. Further, the cosputtered films show a slight reduction in leakage current. The leakage current density may be significantly reduced below 3 x 10(-10) A cm(-2) at an electric field of 0.25 MV/cm when applying the proper radio-frequency bias to the substrate. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3186643] All rights reserved.