Effective suppression of leakage current in SnOx thin films enabled by low-concentration Al doping

초록

SnO2 inherently exhibits a high carrier concentration, which, while beneficial for conductivity, poses reliability challenges in electronic devices, including leakage current, threshold voltage drift, and overall performance degradation. To address these issues and enhance device stability, this study demonstrates that low-concentration Al doping via atomic layer deposition (ALD) effectively modulates the carrier density of SnOx thin films, leading to improved electrical properties. Optimized 2 % Al-doped SnOx thin films, annealed at 600 °C in oxygen for 1 h, exhibit enhanced device performance, achieving a mobility of 2.87 cm2/V·s, a leakage current reduction from 10−8 A to 10−10 A, and an on-off ratio of 106. X-ray photoelectron spectroscopy (XPS) analysis reveals a significant reduction in oxygen vacancies after Al doping, which plays a crucial role in suppressing leakage pathways and stabilizing the threshold voltage. These improvements contribute to enhanced device reliability and electrical stability. Furthermore, the tailored Al doping strategy not only effectively controls the carrier concentration but also preserves the intrinsic conductivity of SnOx, making it a promising approach for high-performance thin-film transistors (TFTs) and optoelectronic applications. This work highlights the effectiveness of precise dopant engineering in optimizing metal oxide semiconductors, providing a scalable strategy to enhance device longevity and functionality. © 2025

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