Characterizations of Amorphous IGZO Thin-Film Transistors With Low Subthreshold Swing

Subthreshold swing (SS) is a key parameter in evaluating the power consumption and material properties of thin-film transistors (TFTs). In this letter, we report an amorphous indium gallium zinc oxide (a-IGZO) TFT with a high-κ SiO₂/HfO₂ gate insulator. The device shows a SS of 96 mV/decade and an on-to-off current ratio of 1.5 × 10¹⁰. The low SS was attributed to the fully depleted channel state, low interface defects, and efficient modulation of the device. With low defect states, the device demonstrates only 2.71% change of operating currents after 1.5 × 10⁴ s stress.