Sol-gel indium-zinc-tin-oxide thin film transistor pixel array with superior stabilityunder negative bias illumination stress

Abstract

In this paper, we fabricate a back channel etched structure thin film transistor (TFT) pixel array with hafnium-aluminum oxide dielectric and indium-zinc-tin-oxide (IZTO) semiconductor using a solution process. The electrical characteristics of IZTO TFT are modified by N₂O plasma treatment. In comparison with the subthreshold swing and saturation mobility of the device untreated by plasma , the subthreshold swing decreases from 204 to 137 mV·dec^–1, and the saturation mobility increases from 29.12 to 51.52 cm²·V^–1·s^–1. Improvement in the mobility and the subthreshold swing (SS) demonstrate that interface states may be passivated by reactive O radicals that are generated by N₂O plasma, which is confirmed by the result of X-ray photoelectron spectrum analysis. In addition, the stability of negative bias illumination stress (NBIS) shift is only 0.1V for 3600 s with an illumination intensity of 10000 lux. This result indicates that its superior stability meets the requirements for the display driver. Therefore, N₂O plasma treatment is verified to be an effective method to improve device performance and light stability for IZTO TFT pixel array.