Novel 4F2 Multi-Bit Dual-Gate 2T0C for High-Density DRAM with Improved Vertical-Channel IGZO TFTs by Self-Aligned Single-Step Process

作者：Fuxi Liao, Zhengyong Zhu, Kaifei Chen, Guanhua Yang, Menggan Liu, Wendong Lu, Zijing Wu, Jiebin Niu, Congyan Lu, Bok-Moon Kang, Jinghong Shi, Xie-Shuai Wu, Richeng Yu, Weidong Zhang, Jing Zhang, Guilei Wang, Jinshan Yue, Jiawei Wang, Lingfei Wang, Di Geng, Nianduan Lu, Chao Zhao, Arokia Nathan, Ling Li, Ming Liu · 年份：2024 · DOI：10.1109/iedm50854.2024.10873464 · 被引用次数：24 · 研究领域：Thin-Film Transistor Technologies、Advancements in Semiconductor Devices and Circuit Design、Semiconductor materials and devices

For the first time, we propose and experimentally demonstrate one novel 4F2vertical-channel IGZO multi-bit dual-gate (DG) 2T0C. Contrary to the sequential integration in single-gate (SG) 4F22T0C, vertical-channel IGZO DG write and read transistors in 4F22TOC are integrated simultaneously by adopting self-aligned single-step (SASS) process. This integration process is not only cost-effective but also releases the typical misalignment, thermal cycling and contamination issues. By this design, the vertical-channel IGZO DG devices show record-high ION of 45.5 f.1A/μm -VTH+1V&VDs=lV and low SS of 68 mV/dec. The 4F2DG 2TOC cell provides reliable read/write operation with high current ratio of IDATA1/IDATAo>300 and long retention time (>470s). Multi-bit storage (2 bit) is also demonstrated for further increasing storage density in this ultra-scaled 4F2cell. This work shows a great prospect for high-density 2TOC DRAM.