This article reports electrical and thermo-physical properties of reactively sputtered HfNx, films with respect to thermal annealing. All metal nitride films were sandwiched between sputtered Si3N4 films. The resulting reduction in electrical resistivity with anneal is explained by a combination of Rutherford backscattering spectrometry and secondary ion mass spectroscopy analyses. The physical mechanisms responsible for the observed anneal behavior are discussed. (C) 2004 American Vacuum Society.