Metal-oxide thin-film transistors (TFTs) promise to enable lightweight and low-power applications, such as ultrathin active matrix displays and low-cost RF identification tags. However, most reported high-performance metal-oxide TFTs contain high-cost indium and gallium elements, leading to constraints in cost-sensitive application. Herein, we present enhancement-/depletion-mode (E-/D-mode) TiO₂ TFTs via $\text{O}_{{2}}/\text{N}_{{2}}$ preannealing of TiO₂ channel material prior to device fabrication process. It is found that the O₂-annealed TiO₂ TFTs exhibit improved performances compared to N₂-annealed TiO₂ TFTs, including increased mobility ( $\mu $ ), higher ON-/OFF-current ratio (I_ON/I_OFF), and lower subthreshold swing (SS). This can be attributed to the passivation effects of O₂ annealing, which leads to less oxygen vacancies at the channel and channel/oxide interface. On the other hand, the ionized oxygen vacancies result in the increased electron concentration in N₂-annealed films and, thus, the negative shift of ${V}_{\text {th}}$ in the TFT performance. This article delivers a possible approach to improve oxide TFT performance by passivation of oxygen vacancies. Furthermore, the controlled annealing process has a great potential in the logic inverter applications when both E- and D-mode TFTs are implemented.

中文翻译：

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通过 O2/N2 预退火的增强型/耗尽型 TiO2 薄膜晶体管

金属氧化物薄膜晶体管 (TFT) 有望实现轻量化和低功耗应用，例如超薄有源矩阵显示器和低成本射频识别标签。然而，大多数报道的高性能金属氧化物 TFT 包含高成本的铟和镓元素，导致对成本敏感的应用的限制。在此，我们通过以下方式展示了增强型/耗尽型（E-/D-mode）TiO ₂ TFT $\text{O}_{{2}}/\text{N}_{{2}}$ 在器件制造过程之前对TiO ₂通道材料进行预退火。发现与 N ₂退火的 TiO ₂ TFT相比，O ₂退火的 TiO ₂ TFT 表现出改进的性能，包括增加的迁移率（ $\亩 $ )、更高的开/关电流比 (I _ON /I _OFF ) 和更低的亚阈值摆幅 (SS)。这可以归因于 O ₂退火的钝化效应，这导致通道和通道/氧化物界面处的氧空位减少。另一方面，电离氧空位导致 N ₂退火薄膜中电子浓度增加，因此， ${V}_{\text {th}}$ 在TFT性能方面。本文提供了一种通过氧空位钝化来提高氧化物 TFT 性能的可能方法。此外，当同时实施 E 和 D 模式 TFT 时，受控退火工艺在逻辑反相器应用中具有巨大潜力。