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.