Thermal and Damp Heat Stability of High-Mobility In_2O_3-Based Transparent Conducting Films Fabricated at Low Process Temperatures

摘要

High electron mobility of transparent conductive oxide (TCO) facilitates highconductivity at a moderate carrier density, resulting in an extension of the degreeof transparency from visible to near-infrared due to less free carrier absorption.These broadband TCO electrodes provide opportunities to improve the performanceof optoelectronic devices. Herein, the thermal and damp heat stabilitycharacteristics of TCO films are described. It is found that the difference in thecrystal growth method has a significant influence on the initial electrical propertiesand stability characteristics. Polycrystalline In_2O_3:Me (Me: W, Ce) filmsdeposited at 200 °C exhibit a relatively high mobility of 70–80 cm~2 V~(-1) s~(-1), arestable after a damp heat test, and improve the mobility of 110–140 cm~2 V~(-1) s~(-1)after postannealing at temperatures greater than the deposition temperature.Conversely, solid-phase crystallized In_2O_3:Me,H films prepared by postannealingamorphous films exhibit an extremely high mobility of 100–160 cm~2 V~(-1) s~(-1);however, they exhibit reduced stability characteristics after the damp heat testand high-temperature annealing process compared to the polycrystalline films.The deterioration of the electrical properties increases as the hydrogen contentin the films increases. The results suggest that polycrystalline and solid-phasecrystallized films should be used properly, according to the device manufacturingprocesses.