Effect of Annealing in a Nitrogen Atmosphere on the Properties of In2O3 Films Deposited with RF Magnetron Sputtering

Abstract

In 2 O 3 films were deposited by RF magnetron sputtering on a glass substrate and then the effect of post deposition annealing in nitrogen atmosphere on the structural, optical and electrical properties of the films was investigated. After deposition, the annealing process was conducted for 30 minutes at 200 and 400 o C. XRD pattern analysis showed that the as deposited films were amorphous. When the annealing temperature reached 200-400 o C, the intensities of the In 2 O 3 (222) major peak increased and the full width at half maximum (FWHM) of the In 2 O 3 (222) peak decreased due to the crystallization. The films annealed at 400 o C showed a grain size of 28 nm, which was larger than that of the as deposited amorphous films. The optical transmittance in the visible wavelength region also increased, while the electrical sheet resistance decreased. In this study, the films annealed at 400 o C showed the highest optical transmittance of 76% and also showed the lowest sheet resistance of 89 Ω/□. The figure of merit reached a maximum of 7.2 × 10 −4 Ω −1 for the films annealed at 400 o C. The effect of the annealing on the work-function of In 2 O 3 films was considered. The work-function obtained from annealed films at 400 o C was 7.0eV. Thus, the annealed In 2 O 3 films are an alternative to ITO films for use as transparent anodes in OLEDs.