Efficient gradient heating-up approach for rapid growth of high-quality amorphous ZrO₂ dielectric films

Abstract

High-k oxide dielectric films are indispensable for low-power-consumption oxide thin-film transistors (TFTs) applied in advanced and portable electronics. However, high-quality oxide dielectric films prepared by solution process typically require sophisticated processes and long thermal annealing time, severely limiting both the throughput manufacturing and cost-effectiveness. In this study, the influence of different heating-up methods on the surface morphology and dielectric properties was systematically investigated. Gradient heating-up method could not only substantially improve the surface morphology and quality of high-k ZrO2 films but also efficiently shorten the annealing time. The gradient heating-up process was further designed on the basis of thermal behavior of the xerogel-like precursor, which successfully realize the preparation of high-quality ZrO2 films with an annealing time of 5 min (i.e. the efficiency of thermal treatment increased by about 89%). The ZrO 2 film presented excellent dielectric properties, including a low leakage current density of ~10−8 A/cm2 (at 2 MV/cm), a large areal capacitance of 169 nF/cm2 and a high dielectric constant of 20.41 (1 MHz). Furthermore, InSnZnO TFT based on the ZrO2 gate dielectrics shows an acceptable device performances, such as a high carrier mobility of 2.82 cm2/V s, a high on/off current ratio of ~105 and a low subthreshold swing of 0.19 V/decade at a low operation voltage of 5 V. This work provide a highly promising approach to fabricate high-quality solution-processed high-k oxide dielectric films employed for large-scale and low-power-consumption electronics.