High-Performance Top-Gate SnO2 Transistors Enabled byDefect Modulation and Interface Engineering Using AtomicLayer Deposition

초록

Achieving high-performance SnO2 field-effect transistors remains challenging due to the difficulty in simultaneously achieving effective carrier control and efficient carrier transport. Here, we address this challenge by combining spatial defect modulation and dielectric interface engineering in top-gate SnO2 field-effect transistors using atomic layer deposition (ALD). A super-cycle ALD process enabled spatially controlled Al incorporation at the bottom, middle, or top of a SnO2 channel, enabling precise modulation of oxygen vacancy-related defects and carrier concentration. Structural and spectroscopic analyses confirm the vertical confinement of Al dopants and the reduction of oxygen vacancy states. Among the configurations, bottom-positioned Al incorporation provides optimized channel characteristics, delivering an on/off current ratio of similar to 105 and a threshold voltage of -0.8 V. To further enhance carrier transport, the influence of HfO2, ZrO2, and Al2O3 gate dielectrics was investigated in a top-gate architecture. While devices with HfO2 and ZrO2 exhibit comparable electrical characteristics, those employing Al2O3 show a mobility enhancement up to similar to 34 cm2/V & centerdot;s. This improvement is attributed to interfacial charge modulation at the Al2O3/SnO2 interface, where defect-mediated carrier supply enhances channel accumulation while mitigating impurity scattering. These results demonstrate that synergistic control of bulk defects and dielectric interfaces provides an effective pathway toward high-performance SnO2 transistors.

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