Structural and electrical characteristics of high-performance stacked YbTixOy/PbZr0.53Ti0.47O3 gate dielectrics for InGaZnO thin-film transistors

摘要

In this paper, we developed high-performance InGaZnO thin-film transistors (TFTs) using three stacked TbTixOy, ErTixOy and YbTixOy/PbZr0.53Ti0.47O3 (PZT) gate dielectrics by rf-sputtering method. The structural properties of stacked TbTixOy, ErTixOy and YbTixOy/PZT dielectric films were studied. Atomic force microscopy, X-ray photoelectron spectroscopy and X-ray diffraction were used to investigate the morphological, chemical and structural features, respectively, of these dielectric films. The inspected structural properties were related to the effecting electrical performances. The InGaZnO TFT device fabricating the stacked YbTixOy/PZT dielectric exhibited the best electrical characteristics, such as a small subthreshold swing of 68 mV/decade, a low threshold voltage of 3 mV, a large electron mobility of 24.4 cm(2)/V-s, and a high I-on/I-off ratio of 5.91 x 10(9). We attribute this behaviour to the YbTixOy film having a higher kappa value as well as a smoother surface. (C) 2020 Elsevier B.V. All rights reserved.