High-performance YbTixOy/PbZr0.53Ti0.47O3 stacked gate dielectric for InGaZnO thin-film transistors

Abstract

In this paper, we developed a high-performance YbTixOy/PbZr0.53Ti0.47O3 (PZT) stacked gate dielectric for indium–gallium–zinc-oxide (InGaZnO) thin-film transistor (TFT) devices. X-ray diffraction, atomic force microscopy, and x-ray photoelectron spectroscopy were applied to examine the crystal structure, film morphology, and elemental composition of the YbTixOy and YbTixOy/PZT stacked films, respectively. Compared with the YbTixOy dielectric, the InGaZnO TFT device with the YbTixOy/PZT stacked dielectric exhibited excellent electrical characteristics in terms of a lower subthreshold swing of 77 mV decade−1, a higher Ion/Ioff current ratio of 3.8 × 109, a smaller threshold voltage of 80 mV, and a larger field-effect mobility of 21.2 cm2 V-s−1. These results are attributed to the YbTixOy/PZT stacked film possessing the high-κ value as well as the smooth interface between the channel layer and dielectric.