Al-doped zinc oxide (ZnO:Al) films for transparent electrodes in thin film solar cells were deposited on glass substrates at a low temperature of $200^{circ}C$ by rf magnetron sputtering. The transmittance of the ZnO:Al films in the visible range was 87%. The lowest resistivity of the ZnO:Al films was about $5.8{ imes}10^{-4}{Omega}$ cm at the Al content of 2.5 wt%. After deposition, the surface of ZnO:Al films were etched in dilute HCl (0.5%) for the investigation of the change in the electrical properties and the surface morphology due to etching.