Single phase of Cu₂O films were deposited by RF magnetron sputter using composite targets containing Cu₂O with 0 and 7 wt % of Cu concentrations, respectively. The films were consequently annealed at temperatures from 250 to 550 ^oC. XRD results showed a phase transformation from Cu₃O₄ → CuO → Cu₂O for the films with 0 wt % Cu as annealing temperature increasing from room temperature to 350 ^oC. An enhancement of crystallization of Cu₂O phase with annealing temperature was found in both films. FESEM demonstrated the grain sizes of both films increased from approximately 25~35 nm to 100~140 nm as annealing temperatures increasing to 550 ^oC. The root mean square (Rms) roughness was approximately 14.8 nm at room temperature and increased up to 46.7 nm at annealing temperature of 550 ^oC for 7 wt % of Cu. As a result, the optimal electrical properties of Cu₂O film was obtained, producing a resistivity of 0.19 Ω·cm, a carrier density of 2.25 × 10¹⁸ cm^-3 and a mobility of 11.2 cm²·V⁻¹·s⁻¹ at annealing temperature of 450 ^oC. The transmittances s in the visible range was found to decrease with increasing annealing temperature, while the optical band gaps are in the order of 2.45-2.63 eV

Keywords: RF magnetron, annealing temperature, electrical resistivity, mobility