Ultra-High Mobility Atomically-Ordered InGaZnO Transistors Through Atomic Layer Deposition

Abstract

Owing to the challenges of downsizing and reducing power consumption in the semiconductor industry, oxide semiconductors such as indium-gallium-zinc-oxide (IGZO) are emerging as notable alternative materials due to their compatibility with back-end-of-line processes and low leakage currents. However, enhancing electrical characteristics of oxide semiconductors to match silicon-based channels remains crucial. In this study, atomically-ordered (AO) IGZO is first synthesized using plasma-enhanced atomic layer deposition, resulting in a transistor with a field-effect mobility of 245 cm2 Vs−1 and excellent switching properties (threshold voltage = 0.17 V, subthreshold swing <75 mV dec−1) in a low thermal budget process (below 250 °C). Theoretical and experimental studies revealed that the ultra-high mobility originates from the carrier quantum confinement induced by the multi-quantum well structure of AO-IGZO. Our approach highlights the potential of oxide semiconductors to surpass limitations of silicon-based technology limitations, thereby paving the way for next-generation channel materials.