A study on electric properties for pulse laser annealing of ITO film after wet etching

The electric properties of ITO thin film after UV or IR laser annealing and wet etching was analyzed via grazing incidence in-plane X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectra and residual stress measurement. The laser annealing process readily induced microcracks or quasi-microcracks on the ITO thin film due to the residual tension stress of crystalline phase transformation between irradiated and non-irradiated areas, and these defects then became the preferred sites for a higher etching rate, resulting in discontinuities in the ITO thin film after the wet etching process. The discontinuities in the residual ITO thin film obstruct carrier transmission and further result in electric failure.

► The laser annealing process induces microcracks in InSnO2 thin films.
► The defects result in higher local etching rate during wet etching.
► These process defects originate from residual tension stress.
► Decreasing the thermal shock is suggested in order to reduce these process defects.