Effect of post-annealing in oxygen environment on ITO thin films deposited using RF magnetron sputtering

Abstract

This work demonstrated the effect of post-annealing on electrical and optical characteristics of indium tin oxide (ITO) thin films. ITO with 100 nm thickness was successfully deposited using radio frequency (RF) magnetron sputtering in oxygen-free environment on sodalime glass substrate without substrate heating. Post-annealing treatment was carried out on ITO thin films in oxygen environment. Different annealing temperatures were studied on the films from 300°C up to 600 °C. The annealing time and oxygen flow rate were kept constant. As the annealing temperature increase, the structure of the thin film’s changes from amorphous to polycrystalline which lead to the effect of enhanced hall mobility. Annealing temperature strongly influence the optical transmission in visible region. It leads to higher transmittance of ITO thin films and is suitable for a blue light emitting diode (LED) application. In addition, higher annealing temperature also enhances film electrical performance. Further characterization of the deposited films was done using hall measurement, UV-Vis spectrophotometer and atomic force microscopic (AFM) to show the improvement on their electrical and optical characteristic. The optical and electrical characteristics of the films have been compared with each other.