Physical and electrical properties of hafnium silicon oxynitride (HfSixOyNz) dielectric films prepared by UV ozone oxidation of hafnium silicon nitride (HfSiN) followed by annealing to 450 degreesC are reported. Interfacial layer growth was minimized through room temperature deposition and subsequent ultraviolet/ozone oxidation. The capacitance-voltage (C-V) and current-voltage (I-V) characteristics of the as-deposited and annealed HfSixOyNz are presented. These 4 nm thick films have a dielectric constant of similar to8-9 with 12 at.% Hf composition, with a leakage current density of 3 X 10(-5) A/cm(2) at V-fb + 1 V. The films have a breakdown field strength > 10 MV/cm. (C) 2004 Elsevier B.V. All rights reserved.