Inductively coupled plasma post-treatment of Al-doped ZnO thin films

Abstract

Thin films of Al-doped zinc oxide (AZO) deposited on glass substrate using the RF magnetron sputter method were post-treated with inductively coupled plasma to enhance the electrical properties of the film. The effects of plasma treatment time and plasma power on the electrical properties of the films were investigated. The crystal structures deposited on the films were characterized by XRD. The resistivity and optical transparency of the films, which are important for its application as a TCO (transparent conducting oxide) material, were measured using the Hall measurement and a UV–VIS spectrophotometer, respectively. Depth-profiling atomic composition of the film was analyzed with Auger electron spectroscopy. The resistivity of the films decreased after plasma treatment from 7.9 × 10 −3 Ωcm to 3.73 × 10 −3 Ωcm without any significant change in the optical transparency. Carrier mobility in the AZO films increased with plasma power up to about 2.2 times that of as-deposited film, while carrier concentrations were nearly constant. From these results, it is confirmed that the enhancement in electrical conductivity of the AZO films is due to increased carrier mobility during treatment of the AZO films with plasma.