Effect of deposition power on structural and electrical properties of Al-doped ZnO films using pulsed direct-current magnetron sputtering with single cylindrical target

Abstract

The change of stoichiometric ratio caused by the increase in sputtering power in Al-doped ZnO (AZO) films was investigated, where the films were grown by pulsed dc magnetron sputtering with a cylindrical target. The properties of the films were strongly affected by the sputtering power. Lower sputtering power was found suitable for the growth of c-axis oriented AZO films. At 2 kW, assisted proper energetic particles, the high quality films having a proper stoichiometric ratio of ZnO were obtained. Whereas, at 4 kW, highly accelerated oxygen ions and recoiling Ar atoms strongly collide with target and these energetic collisions then degrade the quality of films. The average carrier concentrations of all the samples were about 1.5×10 21 cm −3. For a sputtering power of 2 kW, the lowest value of resistivity was estimated to be 7.69×10 −4 Ω cm along with the highest Hall mobility of 6.2 cm 2 V −1 s −1. The deposition rate of AZO films at this power was 130.8 nm/min. The lower sputtering power (2 kW) was found suitable for the fabrication of low-cost transparent conductive oxide layer for futuristic electronic devices with a transmittance of 85%.