Investigation of High-Performance ITO-Stabilized ZnO TFTs With Hybrid-Phase Microstructural Channels

Abstract

In this paper, the properties of hybrid-phase microstructural indium tin oxide-stabilized ZnO thin films and the relevant high-performance thin-film transistors (TFTs) were systematically investigated. The optically extracted Urbach energy revealed that such thin films owned less band-tail state trapping in comparison with that of the corresponding amorphous thin films. This was determined by better atomic arrangement and might realize higher drift mobility theoretically. The influence of deposition parameters such as oxygen partial pressure ratio (P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">O2</sub> ) and direct-current power (PDC) on thin films was discussed in detail. Then, the TFTs with optimal co-sputtering conditions were fabricated. Such devices exhibited a typical field-effect mobility of 26.1 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /V·s, threshold voltage of 0.5 V, on-off ratio of over 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">9</sup> , and extremely low subthreshold swing of 89 mV/decade. Meanwhile, the spatial uniformity, air stability, and repeated switching behavior of devices were demonstrated to be excellent.