Thermal Oxidation of Niobium Nitride Films at Temperatures from 20°–400°C: I . The Surface Reaction

The air oxidation of cubic has been studied by Auger electron spectroscopy at temperatures from ambient to 400°C. At temperatures of 180°C or less, only the first one or two monolayers are oxidized, the reaction product being an oxynitride of niobium. Above 200°C, oxidation is not limited and obeys a linear rate law. At these higher temperatures, the reaction product initially is an oxynitride but, as the reaction proceeds, eventually becomes . The reaction proceeds by the diffusion of oxygen through the reaction product to the interface. Grain boundary diffusion of oxygen into the is rapid and competes with the oxidation reaction.