Large area deposition of ITO films by cluster type sputtering system

The preparation of large area ITO films for transparent electrodes of liquid crystal display (LCD) devices by a cluster type sputtering system (Anelva C-3500) was carried out. Effects of sputtering pressure and introduced oxygen gas flow rate at a low substrate temperature of 10°C on crystal structure, electrical property and etching properties were measured. Amorphous films could be obtained at a sputtering pressure higher than 2.6 Pa and an introduced oxygen gas flow rate lower than 0.8 sccm. During the measurement of etching properties of these films, an etching rate > 80 nm/s and a uniformity of about ±20% were obtained. The sheet resistance could not be reduced to a practical level for LCD devices even after annealing. To obtain a uniform and high etching rate and a low sheet resistance at a practical level, the parameters should be optimized. Although the film was not completely amorphous, an average value of 27 nm/s and a uniformity of ±23.5% for the etching rate was obtained within an area of 370 × 470 mm on a 400 × 500 mm substrate and an average sheet resistance of about 30 ω/□ was also obtained after annealing.