HfO2xNx films have been deposited by high-power impulse magnetron sputtering in an Ar-O<inf>2</inf>-N<inf>2</inf> atmosphere with a series of nitrogen partial pressures. X-ray absorption spectroscopy revealed the optimum deposition conditions required to passivate O vacancies in the HfO<inf>2-x</inf>N<inf>x</inf> films by nitrogen. Low-mobility interstitial species prevent crystallisation of nitrogen-incorporated films. These effects combine to remove leakage paths resulting in superior breakdown strengths compared to films deposited without nitrogen. The bandgap was maintained at ∼5.9eV in the films in which nitrogen passivated the oxygen vacancies. This is essential to provide sufficient band offsets for HfO<inf>2-x</inf>N<inf>x</inf> films to be used an effective gate dielectric.
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