Excimer Laser Crystallization of Amorphous Indium-Tin-Oxide and Its Application to Fine Patterning

Polycrystalline indium-tin-oxide (ITO) thin films were prepared at an ambient temperature by irradiation of amorphous (a-) ITO with KrF excimer laser pulses of ≥40 mJ/cm²/pulse. Electrical resistivity of the specimen at ∼300 K decreased from 5.9×10^-4 Ω·cm to 2.7×10^-4 Ω·cm upon laser crystallization. Irradiation of a-ITO thin films through a phase mask led to the formation of a periodic structure composed of a-ITO and crystalline (c-) ITO. The micropattern of c-ITO was successfully formed by the chemical etching of the irradiated specimens, utilizing the large differences in the chemical etching rate between crystallized and amorphous ITOs.