Natural Oxidation of Ultra-Thin Copper Films

The paper examines the oxidation of polycrystalline Cu films under the impact of ambient atmosphere in the course of extended time (from 20 to 90 days). It shows that in the case of 10 nm thick Cu films deposited onto the glass substrate by method of magnetron sputtering, one eventually observes the increase in transparency, surface resistance and surface roughness, as well as the decrease in reflection in the area of near infrared region. The most dramatic changes occur in films deposited in the pulse mode of sputtering with frequency of 3 kHz compared to films deposited in the direct current mode. Formation of sublayer ZnO:Al and 20 nm thick upper passivating layer ZnO:Al allows effectively preventing the oxidation of thin copper films under the impact of ambient atmosphere.