Strategy toward High-Mobility Oxide Semiconductor Thin-Film Transistors by Atomic Layer Deposition

In this work, we discuss a strategy for high-mobility oxide semiconductor based on atomic layer deposition process. First, to employ high In content thin film to boost the mobility. Second, to take the advantage of atomically thin film by atomic layer deposition to suppress the crystallization and to form the amorphous phase. Third, to use the quantum confinement effect in nanoscale thickness to modulate the carrier density. As in conventional sputtering deposition approach without the capability of atomically thickness control, high In content films usually lead to high carrier density and crystallization so that carrier concentration is usually too high for practical device. Thus, ALD is an ideal process to realize ultra-thin channel for high mobility oxide semiconductors.