Hybrid-contact Schottky-barrier IGZO thin-film transistors with low barrier sensitivity and high stability

Abstract

In this work, we investigated the electrical characteristics of Schottky-barrier indium–gallium–zinc oxide (IGZO) thin-film transistors (SBTFTs) by simulation and experiment. The effects of barrier height and channel layer thickness on the electrical properties of hybrid-contact vs single-contact SBTFTs were systematically explored via simulation. The results showed that devices utilizing hybrid-contact architectures exhibit higher output currents and are much less sensitive to variations in barrier height compared to single-contact devices, implying that these devices can more easily achieve consistent electrical properties. Experimentally, hybrid-contact IGZO SBTFTs were fabricated using chemically stable cobalt (Co) as the source/drain electrodes. The devices, utilizing an optimized two-step annealing process, exhibited ultra-small hysteresis and excellent electrical stability under both negative bias illumination temperature stress and positive bias temperature stress. The underlying mechanism responsible for the suppressed hysteresis was thoroughly analyzed. This work opens up a feasible way toward fabricating low-cost metal-oxide SBTFTs with minimized barrier sensitivity and high stability.