Radio frequency sputter deposition of single phase cuprous oxide using Cu2O as a target material and its resistive switching properties

Single phase cuprous oxide (Cu2O) thin films were deposited on TiN substrate with radio frequency sputtering. Cu2O was used as a target material without oxygen to avoid the formation of Cu2O and CuO mixture which was formed in copper oxidation or when using Cu target along with Ar and O2. Single phase cuprous oxide was confirmed with X-ray diffraction and X-ray photoelectron spectroscopy measurements. Typical growth rate of Cu2O thin film was 14 nm/min under the optimized process condition. Cu2O thin films were thermally stable up to 250 deg. C , while the phase separation occurred above 350 deg. C . Fundamental properties of Cu2O thin films such as resistivity, mobility, and dielectric constant were obtained. Current-voltage characteristics of Pt/Cu2O/TiN-based structure showed two stable resistance states through the double voltage sweep between - 2 V and + 2 V. The electrical properties of this structure were described well with space charge-limited conduction mechanism and the full energy-band structure of Cu2O film was obtained