High Efficiency Nitrogen Incorporation Technique Using Ultraviolet Assisted Low Temperature Process For Hafnia Gate Dielectric

An evaluation of a low temperature process (similar to 350 degrees C) for nitrogen incorporation in hafnia gate dielectric has been reported. This method is based on postdeposition nitridation under ultraviolet light illuminated NH3 ambience. X-ray photoelectron spectroscopy confirmed the amount of nitrogen incorporated by this process was comparable to that of high temperature (similar to 650 degrees C) thermal nitridation (similar to 7%). Uniformity of nitrogen distribution in the film was analyzed by secondary ion mass spectroscopy. A capacitance density of similar to 3.96 mu F/cm(2) with 9.4 A equivalent oxide thickness and 10 A thick interface layer were obtained by ultraviolet assisted nitridation process. (c) 2008 American Institute of Physics.