In-situ optical view onto copper oxidation – role of reactive interfaces and self-heating

Abstract UV/Vis transmission spectroscopy is employed to monitor the oxidation of polycrystalline Cu films at different thermodynamic conditions. The resulting spectral series are fitted with a three-layer model based on Bruggeman’s theory. The simulations provide insight into the Cu2O growth kinetics and the morphology of the metal-oxide interface. In contrast to classical oxidation theories, the oxide growth shows an accelerated behavior, being explained with a corrugated metal-oxide interface due to preferred oxidation along grain boundaries and a gradual temperature rise in the exothermic process. After accounting for these effects, the Cu2O growth curves are well reproduced for various oxidation conditions.