We investigated Gd2O3 and Zr-incorporated Gd2O3 films grown on Si (100) as a function of nitridation temperature under an NH3 ambient and the incorporation of Zr into the film. The formation of a silicide layer at the interfacial region was suppressed in cases of ZF-incorporated or NH3-nitried Gd2O3 films. The crystalline structure was affected when zirconium, With a relatively small ionic radius, was substituted with gadolinium. When the concentration of Zr atoms in a Gd2O3 film reaches a specific level (Gd0.6Zr1.9O4.3), phase transition occurred from cubic Gd2O3 to monoclinic ZrO2. However, the monoclinic phase disappeared after nitridation at 900 degrees C in an NH3 ambient. The majority of the nitrogen atoms accumulated near the interface in the films and the concentration of incorporated N increased with increasing Zr content and NH3 annealing temperature. Moreover, nitrogen atoms bonded to Zr-silicate at the interface, in preference to ZrO2 in the film. These incorporation characteristics of nitrogen into Zr-incorporated Gd2O3 film have an effect on the thermal stability and crystalline structure of a film. (C) 2009 Elsevier B.V. All rights reserved.