High-performance YbTi_xO_y/PbZr_0.53Ti_0.47O₃ stacked gate dielectric for InGaZnO thin-film transistors

In this paper, we developed a high-performance YbTi_xO_y/PbZr_0.53Ti_0.47O₃ (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 YbTi_xO_y and YbTi_xO_y/PZT stacked films, respectively. Compared with the YbTi_xO_y dielectric, the InGaZnO TFT device with the YbTi_xO_y/PZT stacked dielectric exhibited excellent electrical characteristics in terms of a lower subthreshold swing of 77 mV decade⁻¹, a higher I_on/I_off 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 YbTi_xO_y/PZT stacked film possessing the high-κ value as well as the smooth interface between the channel layer and dielectric.