Mechanical and electrical properties of copper oxide thin films formed by thermal oxidation

We investigate the mechanical and electrical properties of cuprous oxide (Cu 2 O) thin films processed by low-temperature oxidation of bulk annealed copper. These oxide layers were characterized using advanced techniques unveiling a microstructure composed of nanocrystalline grains. Mechanical and electrical properties were assessed through the combination of electrical-nanoindentation experiments and multiphysics numerical simulation by the Finite Element Method. Regarding the mechanical aspect, the oxide film elastic modulus was determined at 22 ± 5 GPa and its plastic behavior was successfully modeled with a Drucker-Prager yield criterion. In addition, the oxide layer was found to act as a non-penetrable barrier against dislocation gliding in the copper substrate near-surface, significantly enhancing size effects. Regarding the electrical aspect, Poole–Frenkel conduction was identified as the driving conduction mechanism in Cu 2 O, with a dielectric permittivity of 7 and a trap level of 320 meV, the latter result suggesting an electrical transport through hole-trapping copper vacancies.