Electrical properties of an oxide semiconductor thin-film transistor (TFT) with a ZnO channel layer and a HfOx gate insulator, both of which are deposited by atomic layer deposition (ALD), are investigated at varying post-annealing temperatures. The TFTs that are post-annealed at 250 and 300 °C show relative low on/off ratios 102 and clockwise hysteresis with a little increased threshold voltage due to electron charging at the trap states in the HfOx/ZnO interface or inside the HfOx gate insulator. The threshold voltage shift, however, is negligible at the gate voltage of +20 V and as low as about 2.2 V at the highest gate voltage of +40 V, which guarantees stable operations of TFTs without significant degradation of electrical performance. The channel mobilities are around 4.0 cm2 V−1 s−1 at this annealing temperature range. The presented results report the dependence of electrical performance such as on/off ratio and electrical instability, possibly caused by electrical charging, on the post-annealing temperature, which requires post-annealing at 350 °C or higher temperatures for stable operations of TFTs with ALD-ZnO and HfOx.

中文翻译：

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具有通过原子层沉积沉积的 ZnO 通道和 HfOx 栅极绝缘体的薄膜晶体管的退火后温度相关电特性

具有 ZnO 沟道层和 HfOx 栅极绝缘体的氧化物半导体薄膜晶体管 (TFT) 的电性能在不同的后退火温度下进行了研究，这两者都是通过原子层沉积 (ALD) 沉积的。由于在 HfOx/ZnO 界面或 HfOx 栅极绝缘体内部的陷阱态电子充电，在 250 和 300 °C 后退火的 TFT 显示出相对较低的开/关比 102 和顺时针滞后，阈值电压略有增加. 然而，阈值电压漂移在 +20 V 的栅极电压下可以忽略不计，在 +40 V 的最高栅极电压下低至约 2.2 V，这保证了 TFT 的稳定运行，而不会显着降低电气性能。在此退火温度范围内，通道迁移率约为 4.0 cm2 V-1 s-1。