To improve electrical properties a high temperature annealing treatment was applied to several transparent conductive oxides TCO , namely tin doped indium oxide ITO , Ga or Al doped ZnO ZnO Al Ga , ion beam assisted deposited IBAD ZnO Ga and Ga doped zinc magnesium oxide ZnMgO Ga . All these films were grown by magnetron sputtering. During the annealing process all TCO films were capped with 50 nm of amorphous silicon in order to protect the films from environmental impact. Increase in mobility up to 72 cm2 Vs and low resistivity of 1.6 10 amp; 8722;4 amp; 937;cm was achieved for ZnO Al after annealing at 650 C for 24 h. Independent of the deposition conditions and doping or alloying material almost all ZnO based films show a consistent improvement in mobility. Also for ITO films a decrease in resistivity with partially improved mobility was found after annealing. However, not all ITO films show consistent improvement, but carrier density above 1021 cm amp; 8722;3 while ZnO films show no clear trend for carrier density but a remarkable increase in mobility. Thus we propose the healing of defects and the activation of donors to be most significant effects for ZnO and ITO films, respectively