The remote plasma nitridation (RPN) of an HfO2 film using N-2 and NH3 has been investigated comparatively. X-ray photoelectron spectroscopy and Auger electron spectroscopy analyses after post-deposition annealing (PDA) at 700 degrees show that a large amount of nitrogen is present in the bulk film as well as in the interfacial layer for the HfO2 film nitrided with NH3-RPN. It is also shown that the interfacial layer formed during RPN and PDA is a nitrogen-rich Hf-silicate. The C-V characteristics of an HfOxNy gate dielectric nitrided with NH3-RPN have a smaller equivalent oxide thickness than that nitrided with N-2-RPN in spite of its thicker interfacial layer. (C) 2010 Elsevier B.V. All rights reserved.