Rapid and facile low-temperature solution production of ZrO2 films as high-k dielectrics for flexible low-voltage thin-film transistors

Abstract

A rapid lightwave (LW) irradiation method was presented for the low-temperature solution production of ZrO2 films as high-k dielectrics for flexible high-performance thin-film transistors (TFTs). The LW irradiation process markedly decreased the required processing temperature and processing time. Microstructure characterizations confirmed the successful formation of ZrO2 films with an ultrasmooth surface, large band gap (>5 eV) and low defect level. The ZrO2 film produced via LW irradiation at ∼200 °C in only 8 min presented excellent dielectric properties, including a small leakage current of 3.3 × 10−8 A/cm2 and a large capacitance of 296 nF/cm2, significantly outperforming the films by the conventional high-temperature annealing process at 400 °C for 60 min. Furthermore, LW irradiation was extended to the channel layer. The rapid low-temperature solution-processed InZrOx TFTs exhibited superior electrical characteristics, such as a high carrier mobility of 41.3 cm2V−1s−1 and a high on-off current ratio of 105∼106 at a low operation voltage of 3 V due to the employment of high-quality ZrO2 dielectric films. Moreover, the flexible TFT on a polyimide (PI) plastic substrate achieved a high mobility of nearly 30 cm2V−1s−1, indicating that LW irradiation is highly promising for the rapid and low-temperature solution production of high-quality and flexible oxide electronic devices.