Robustness of Passivated ALD Zinc Tin Oxide TFTs to Aging and Bias Stress
Robustness of Passivated ALD Zinc Tin Oxide TFTs to Aging and Bias Stress
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DOI：
10.1109/ted.2022.3216791
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发表时间：
2022-12
影响因子：
3.1
通讯作者：
C. Allemang;Tae H. Cho;N. Dasgupta;R. L. Peterson
中科院分区：
文献类型：
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作者：
C. Allemang;Tae H. Cho;N. Dasgupta;R. L. Peterson
由非晶态氧化物半导体(AOS)制成的薄膜电子因其优越的电子传输性能而被研究用于超显示技术。为了扩大商业应用，需要使用可伸缩沉积技术制造坚固的器件。在这里，我们使用原子层沉积(ALD)沉积的氧化锡锌制备底栅、顶接触薄膜晶体管(TFT)，并研究在黑暗空气环境中存储的器件在氧化铝钝化和不钝化的情况下对老化和偏压的稳健性。所有样品都表现出出色的流动性($\MU_{\Text{FE}}$)和亚阈值摆动(SS)对老化的稳健性。大部分设备老化发生在前25天内，之后性能趋于稳定。由与周围分子的相互作用主导的正偏压引起的变化通过钝化大大减少。然而，钝化会导致接触电阻、SS和负偏压照明应力(NBIS)的不稳定性增加。钝化过程中氧空位的扩散导致{R}{C}}的增加，而SS和NBIS不稳定性的增加则归因于亚能隙界面缺陷。实验结果与SilVaco ATLAS模拟结果进行了比较，以确认所提出的物理机制，并允许量化相关的缺陷和非理想性。
Thin-film electronics fabricated with amorphous oxide semiconductors (AOS) are being studied for beyond-display technologies because of their superior electron transport. To widen the commercial applications, robust devices fabricated using scalable deposition techniques are required. Here, we fabricate bottom-gate, top contact thin-film transistors (TFTs) using zinc tin oxide, an AOS deposited by atomic layer deposition (ALD), and study robustness to aging and bias stress for devices stored in a dark air ambient with and without Al2O3 passivation. All samples exhibit excellent mobility ( $\mu _{\text {FE}}$ ) and subthreshold swing (SS) robustness to aging. Most of the device aging occurs within the first 25 days, after which the performance stabilizes. Changes due to positive bias stress, which are dominated by interactions with ambient molecules, are greatly reduced by passivation. Passivation, however, results in an increase in contact resistance ( ${R}_{C}$ ), SS, and negative bias illumination stress (NBIS) instability. The increase in ${R}_{C}$ is attributed to the diffusion of oxygen vacancies that occurs during the passivation process, while the increase in SS and NBIS instability is attributed to subgap interface defects. The experimental results are compared to Silvaco ATLAS simulations to confirm the proposed physical mechanisms and allow quantification of the associated defects and non-idealities.