High-performance low voltage operation of indium zinc tin oxide thin film transistors using chemically derived sodium β-alumina dielectric

Abstract

We present high performance, low voltage (≤ 3 V) operation of thin film transistors (TFTs) with indium zinc tin oxide (IZTO: In4Sn4ZnO15)-semiconductor. The film of IZTO was fabricated via low-temperature (200 °C) solution combustion processing without incorporating an external fuel. As 2-methoxyethanol is a widely used organic solvent due to its high dissolution capability, serve the purpose of both the solvent and the fuel. On quantification from the balanced redox reaction, 0.3% of 2-methoxyethanol assisted for the action of fuel and helped in the formation of metal oxide, and the rest (99.7%) served the purpose of being dissolution medium. The balanced redox chemistry yielded a significant fraction of (56.5%) metal oxide at 200 °C confirmed via high-resolution oxygen 1s spectrum. Further, the chemically derived thin film of sodium β-alumina with a dielectric constant of ~ 21, while annealing at 350 °C incorporated in the TFT for the realization of low voltage operation. The performance assessment is systematically carried out both silicon dioxide (SiO2) and sodium β-alumina and found that the TFTs with SiO2 and IZTO exhibited a saturation mobility (µsat), Ion/Ioff ratio and the threshold voltage (Vth) of 0.50 ± 0.02 cm2 V−1 s−1, 1.25 × 104 and 6.6 ± 0.79 V respectively. While changing the dielectric to sodium β-alumina presented a µsat, Ion/Ioff ratio and Vth of 4.21 ± 0.18 cm2 V−1 s−1, 1.4 × 102 and 0.47 ± 0.08 V respectively.