STUDY ON ITO THIN FILMS PREPARED BY MULTI-ANNEALING TECHNIQUE

Abstract

Indium tin oxide (ITO) thin films have been successfully prepared by a solution process followed by a multi-annealing method. In this study, we focus on the use of multi-annealing method, for which each layer was annealed at a suitable temperature, instead of a conventional annealing way, by means of a rapid thermal annealing system, in order to improve the film quality. The crystalline structure and surface morphology of the ITO thin films were investigated by using X-ray diffraction (XRD) spectrometer, atomic force microscope (AFM) and scanning electron microscope (SEM). It has been obtained that all of ITO films exhibit a single phase with (222)- and (440)-preferred orientations. The AFM and SEM observations show that the particle size of ITO films was about 10 nm and the ITO film thickness was 180 nm, respectively. In sequence, the electrical properties of ITO thin films were evaluated by using four-point probe and Hall effect measurement methods, and the optical properties were investigated by UV/VIS spectrometer. The results show that the best ITO films have electrical resistivity of 2.6 × 10-3 Ω.cm and transparency higher than 90 %, which strongly supports to the application of electrode in solar cell, LED or transistor devices from viewpoints of low-cost production and low-energy consumption.