Highly Stable Thin-Film Transistors Based on Amorphous Perovskite Semiconductors

Abstract

In this work, Indium-free amorphous Zn-Ba-Sn-O (ZBTO) thin films and resulting thin-film transistor (TFT) characteristics were investigated. ZBTO films were fabricated by co-sputtering system, using ZnSnO3 (ZTO) and BaSnO3 (BTO) ceramic targets. The BaSnO3 was selected because of its relatively large heat of formation compared to ZTO, and therefore enhancing structural ordering and less defective structure. The applied BTO target power was varied to investigate Ba content effect on TFT performances. X-ray photoelectron spectroscopy (XPS) and absorption spectra revealed that the subgap states including tail states were significantly suppressed by Ba incorporation. Moreover, it was found that the optimized ZBTO TFTs shown field effect mobility value over 20 cm2/Vs in saturation regime, and ultrastable stability (ΔVth < 1.0 V) under negative bias illumination stress (NBIS).