Department of Applied Physics, Korea University, Sejong, Korea.
Nanotechnology. 2016 Aug 12;27(32):325203. doi: 10.1088/0957-4484/27/32/325203. Epub 2016 Jul 1.
Hydrogen in zinc oxide based semiconductors functions as a donor or a defect de-activator depending on its concentration, greatly affecting the device characteristics of oxide thin-film transistors (TFTs). Thus, controlling the hydrogen concentration in oxide semiconductors is very important for achieving high mobility and minimizing device instability. In this study, we investigated the charge transport dynamics of the amorphous semiconductor InGaZnO at various hydrogen concentrations as a function of the deposition temperature of the gate insulator. To examine the nature of dynamic charge trapping, we employed short-pulse current-voltage and transient current-time measurements. Among various examined oxide devices, that with a high hydrogen concentration exhibits the best performance characteristics, such as high saturation mobility (10.9 cm(2) v(-1) s(-1)), low subthreshold slope (0.12 V/dec), and negligible hysteresis, which stem from low defect densities and negligible transient charge trapping. Our finding indicates that hydrogen atoms effectively passivate the defects in subgap states of the bulk semiconductor, minimizing the mobility degradation and threshold voltage instability. This study indicates that hydrogen plays a useful role in TFTs by improving the device performance and stability.
氧化锌基半导体中的氢根据其浓度可以作为施主或缺陷钝化剂，极大地影响氧化物薄膜晶体管（TFT）的器件特性。因此，控制氧化物半导体中的氢浓度对于实现高迁移率和最小化器件不稳定性非常重要。在这项研究中，我们研究了非晶半导体 InGaZnO 在不同氢浓度下的电荷输运动力学，作为栅极绝缘层沉积温度的函数。为了研究动态电荷俘获的性质，我们采用了短脉冲电流-电压和瞬态电流-时间测量。在所研究的各种氧化物器件中，氢浓度较高的器件表现出最佳的性能特性，如高饱和迁移率（10.9 cm(2) v(-1) s(-1)）、低亚阈值斜率（0.12 V/dec）和可忽略的迟滞，这归因于低缺陷密度和可忽略的瞬态电荷俘获。我们的发现表明，氢原子有效地钝化了体半导体亚带隙状态中的缺陷，最大限度地减少了迁移率退化和阈值电压不稳定性。这项研究表明，氢通过改善器件性能和稳定性在 TFT 中发挥了有益的作用。
