Effects of RF power on the growth behaviors of CuAlO2 thin films

Cu-Al-O thin films were deposited on glass substrates by radio frequency (RF) sputtering using an Al-Cu mosaic target under various RF powers at room temperature. The RF power was set at 100, 200, 250, and 300 W and the oxygen partial pressure (O2/Ar+O2) was set at 10%. This study examined the crystal structure, electronic structure, valence state, and electrical resistivity properties of the CuAlO2 thin films as a function of RF power and growth rate. The Cu/Al atomic ratios when the RF power was set at 100, 200, 250, and 300 W were 0.9, 1, 1.1, and 0.9, respectively. As RF power increased, the crystal structure of the Cu-Al-O film changed from amorphous to crystallized CuAlO2. In addition, the results also show that the growth rate could influence the phase formation behavior. The lowest resistivity of the Cu-Al-O thin films obtained in this study was 1.9 kΩ-cm with 250 W at room temperature.