Femtosecond Laser-induced Crystallization of Amorphous Indium Tin Oxide Film on Glass Substrate for Patterning Applications

A method is proposed for patterning crystalline indium tin oxide (c-ITO) structures on amorphous ITO (a-ITO) thin films using a femtosecond laser. In the proposed approach, the a-ITO film is transformed into a c-ITO film over a predetermined area of the glass substrate via the heat energy supplied by the laser beam and the unirradiated a-ITO film is then removed using an acidic etchant solution. The c-ITO patterns are observed using scanning electron microscopy (SEM). The results confirm that the pattern width can be precisely controlled via an appropriate selection of the repetition rate, laser power and scanning speed. In addition, the experimental results show that a high repetition rate (80 MHz) reduces the thermal cycling effect and yields a corresponding improvement in the surface properties of the c-ITO patterns.