Lee Minuk, Jo Jeong-Wan, Kim Yoon-Jeong, Choi Seungbeom, Kwon Sung Min, Jeon Seong Pil, Facchetti Antonio, Kim Yong-Hoon, Park Sung Kyu
School of Electrical and Electronic Engineering, Chung-Ang University, Seoul, 06974, Korea.
SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, Korea.
Adv Mater. 2018 Aug 27:e1804120. doi: 10.1002/adma.201804120.
A new strategy is reported to achieve high-mobility, low-off-current, and operationally stable solution-processable metal-oxide thin-film transistors (TFTs) using a corrugated heterojunction channel structure. The corrugated heterojunction channel, having alternating thin-indium-tin-zinc-oxide (ITZO)/indium-gallium-zinc-oxide (IGZO) and thick-ITZO/IGZO film regions, enables the accumulated electron concentration to be tuned in the TFT off- and on-states via charge modulation at the vertical regions of the heterojunction. The ITZO/IGZO TFTs with optimized corrugated structure exhibit a maximum field-effect mobility >50 cm V s with an on/off current ratio of >10 and good operational stability (threshold voltage shift <1 V for a positive-gate-bias stress of 10 ks, without passivation). To exploit the underlying conduction mechanism of the corrugated heterojunction TFTs, a physical model is implemented by using a variety of chemical, structural, and electrical characterization tools and Technology Computer-Aided Design simulations. The physical model reveals that efficient charge manipulation is possible via the corrugated structure, by inducing an extremely high carrier concentration at the nanoscale vertical channel regions, enabling low off-currents and high on-currents depending on the applied gate bias.
据报道，一种新策略可实现具有高迁移率、低关态电流且操作稳定的可溶液加工金属氧化物薄膜晶体管（TFT），该策略采用波纹状异质结沟道结构。波纹状异质结沟道具有交替的薄铟锡锌氧化物（ITZO）/铟镓锌氧化物（IGZO）和厚ITZO/IGZO薄膜区域，能够通过异质结垂直区域的电荷调制，在TFT的关态和开态调节累积电子浓度。具有优化波纹结构的ITZO/IGZO TFT表现出最大场效应迁移率>50 cm² V⁻¹ s⁻¹，开/关电流比>10且具有良好的操作稳定性（对于10 ks的正栅极偏置应力，阈值电压偏移<1 V，无钝化）。为了探究波纹状异质结TFT的潜在传导机制，通过使用各种化学、结构和电学表征工具以及技术计算机辅助设计模拟来实现一个物理模型。该物理模型表明，通过波纹状结构可以实现有效的电荷操纵，即在纳米级垂直沟道区域诱导极高的载流子浓度，从而根据施加的栅极偏置实现低关态电流和高开态电流。
