Contact Engineering for High-Performance N-Type 2D Semiconductor Transistors
Yuxuan Lin, Pin‐Chun Shen, Cong Su, Ang‐Sheng Chou, Tong Wu, C.-C. Cheng, Ji Hoon Park, Ming‐Hui Chiu, Ang‐Yu Lu, Hao‐Ling Tang, Mohammad Mahdi Tavakoli, Gregory Pitner, Xiang Ji, Christina McGahan, Xinwei Wang, Zhengyang Cai, Nannan Mao, Janet Z. Wang, Yuxuan Wang, William A. Tisdale, Xi Ling, Katherine Aidala, Vincent Tung, Jingbo Li, Alex Zettl, C.-I. Wu, Jing Guo, H. Wang, Jeffrey Bokor, Tomás Palacios, Lain‐Jong Li, Jing Kong
Abstract
Two-dimensional (2D) semiconductors are expected to have exceptional properties for ultimately scaled transistors, but forming ohmic contact to them has been challenging, which tremendously limit the transistor performance. In this paper, we review the recent research progress on the elimination of different gap-state pinning effects, including defect-induced gap states (DIGS) and metal-induced gap states (MIGS). Specifically, an oxygen passivation method and a semimetallic contact technology were developed to reduce the DIGS and MIGS, respectively. Based on these approaches, much improved contact resistance and on-state current were observed. Key device metrics were extracted on these high-performance transistors, which reveals future directions for further improving the device performance.