Approach to High-Performance Indium Gallium Zinc Oxide Transistors by Thermal Atomic Layer Deposition

Amorphous indium gallium zinc oxide (a-IGZO) thin films have been investigated to meet the high-resolution demands of augmented reality (AR) and virtual reality (VR) applications. In this study, we report on thin-film transistors (TFTs) derived from fully thermal atomic layer deposition (ALD), using IGZO as the channel layer and Al2O3 as the gate dielectric. By optimizing the deposition sequence and post-treatment processes, we achieved a high field-effect mobility of 52.5 cm2/Vs and a steep subthreshold swing of 116 mV/decade. This exceptional performance is attributed to the elevated In2O3 content in the IGZO thin films, which induces a substantial increase in sub-gap states adjacent to the conduction band minimum (CBM) and valence band maximum (VBM) while concurrently reducing the bandgap. At an elevated measurement temperature of 125 °C, the device exhibited an enhanced field-effect mobility of 60.4 cm2/Vs. These findings offer a new approach for optimizing metal oxide-based electronics.