Min Won Kyung, Park Sung Pyo, Kim Hee Jun, Lee Jin Hyeok, Park Kyungho, Kim Dongwoo, Kim Ki Woo, Kim Hyun Jae
School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea.
ACS Appl Mater Interfaces. 2020 Jun 3;12(22):24929-24939. doi: 10.1021/acsami.0c01530. Epub 2020 May 21.
P-type copper oxide (CuO) thin-film transistors (TFTs) with enhanced switching characteristics were fabricated by introducing a sputter-processed capping layer capable of controlling the back-channel phase (labeled as phase-controlling layer, PCL). By optimizing the processing conditions (the deposition power and postdeposition annealing parameters), the switching characteristics of the TFTs achieved a subthreshold swing of 0.11 V dec, an on/off current ratio (/) of 2.81 × 10, and a field-effect mobility (μ) of 0.75 cm V s, a considerable enhancement in performance compared to that of CuO TFTs without the PCL. Through optical/electrical analyses and technology computer-aided design simulations, we determined that the performance improvements were because of the CuO back-channel phase reconstruction through PCL deposition and subsequent annealing. The two factors that occurred during the process, sputtering damage and heat treatment, played key roles in creating the phase reconstruction by inducing a local phase transition that sharply reduced the off-current via controlling back-channel hole conduction. As a sample application, we fabricated a complementary metal oxide semiconductor inverter based on our optimized CuO TFT and an InGaZnO TFT that demonstrated a large inverter voltage gain of >14. The proposed approach opens up advancements in low-power circuit design by expanding the utilization range of oxide TFTs.
通过引入能够控制背沟道相的溅射处理覆盖层（标记为相控层，PCL），制备了具有增强开关特性的P型氧化铜（CuO）薄膜晶体管（TFT）。通过优化工艺条件（沉积功率和沉积后退火参数），TFT的开关特性实现了0.11 V/dec的亚阈值摆幅、2.81×10的开/关电流比（Ion/Ioff）以及0.75 cm²/V·s的场效应迁移率（μ），与没有PCL的CuO TFT相比，性能有了显著提高。通过光学/电学分析和技术计算机辅助设计模拟，我们确定性能的提高是由于通过PCL沉积和随后的退火实现了CuO背沟道相重建。该过程中出现的两个因素，溅射损伤和热处理，通过诱导局部相变在创建相重建中起关键作用，该相变通过控制背沟道空穴传导大幅降低了关态电流。作为一个示例应用，我们基于优化后的CuO TFT和InGaZnO TFT制造了一个互补金属氧化物半导体反相器，其展示出大于14的大反相器电压增益。所提出的方法通过扩大氧化物TFT的应用范围，为低功耗电路设计开辟了新进展。
