Optimized performance and stability of ultra-thin ITO oxide transistors through air annealing strategy

High-performance and highly-stable oxide transistors are essential for the development of advanced memory devices and monolithic 3D integration. In this study, high-k ultra-thin ITO transistor with 45 min air annealing process is demonstrated, which achieves a mobility of 86.5 cm 2 /V·s, a subthreshold swing (SS) of 80.4 mV/decade, a minimal hysteresis window of −0.15 V, and a low gate leakage current of 5.5 pA. Furthermore, the 45-min air-annealed ITO transistors also exhibit remarkable stability under negative and positive bias stress (NBS and PBS) conditions. In addition, optimizations in subthreshold swing (SS), and stability is enhanced with increase in annealing time, but the slight mobility degradation is caused by prolonged annealing . The underlying mechanism is revealed by X-ray photoelectron spectroscopy (XPS) analysis and Line-Energy Dispersive Spectroscopy (EDS). The results indicate that the reduction of oxygen vacancies , which mainly occur in HfO 2 , and at the surface of ITO contributes significantly to the improved electrical performance and stability of ultra-thin ITO transistor. Finally, a depletion-mode inverter cell based on the air-annealed ITO transistor is demonstrated, highlighting the potential of ITO transistors in the field of integrated circuits (ICs). • Electrical performance and stability of ITO transistor are optimized by air annealing strategy. • 45-min air annealed ITO transistor performs the best with high electrical performance and excellent stability. • High performance inverter cell is demonstrated with gain of 150 V/V at V DD of 2 V. • Optimized mechanism is based on the reduction of Vo in ITO and HfO 2 films.