Analysis of Interface Phenomena for High-Performance Dual-Stacked Oxide Thin-Film Transistors via Equivalent Circuit Modeling

Oxide thin-film transistors (TFTs) have attracted much attention because they can be applied to flexible and large-scaled switching devices. Especially, oxide semiconductors (OSs) have been developed as active layers of TFTs. Among them, indium–gallium–zinc oxide (IGZO) is actively used in the organic light-emitting diode display field. However, despite their superior off-state properties, IGZO TFTs are limited by low field-effect mobility, which critically affects display resolution and power consumption. Herein, we determine new working mechanisms in dual-stacked OS, and based on this, we develop a dual-stacked OS-based TFT with improved performance: high field-effect mobility (∼80 cm 2 /V·s), ideal threshold voltage near 0 V, high on–off current ratio (>10 9 ), and good stability at bias stress. Induced areas are formed at the interface by the band offset: band offset-induced area (BO…