Preparation of Cu–O Films by Sputtering Using He Gas

Abstract
Cu–O films have been deposited by rf sputtering using a mixture of Ar, He and O2 as a sputtering gas. When He was mixed with the sputtering gas, highly oxidized Cu–O films were obtained with low O2 content of the sputtering gas, compared with those deposited without He. Activated particles in the plasma were investigated by optical emission spectroscopy analysis. This enhancement of oxidation of Cu–O films is related to an increase in O2 + and O* generated through the Penning ionization process by He m in neutral excited metastable states.