Computational Screening and Multiscale Simulation of Barrier-Free Contacts for 2D Semiconductor pFETs
Ning Yang, Yuxuan Lin, Chih‐Piao Chuu, Saifur Rahman, Tong Wu, Ang‐Sheng Chou, San‐Lin Liew, Kohei Fujiwara, Hung‐Yu Chen, Junya Ikeda, Atsushi Tsukazaki, Duen‐Huei Hou, Wei-Yen Woon, Szuya Sandy Liao, Shengxi Huang, Xiaofeng Qian, Jing Guo, Iuliana Radu, H.‐S. Philip Wong, Han Wang
Abstract
Low-resistance p-type contacts to two-dimensional (2D) semiconductors remains a critical challenge towards the industrial application of 2D channel materials in advanced logic technology. To address this challenge, we computationally screen and identify designs for ultralow-resistance p-type contacts to 2D semiconductors such as WSe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> by combining ab initio density-functional-theory (DFT) and quantum device simulations. Two new contact strategies, van der Waals metallic contact (such as 1H-NbS <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> ), and bulk semimetallic contact (such as Co <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> ), are identified as realistic pathways to achieving Schottky-barrier-free and low-contact-resistance p-type contacts for 2D semiconductor pFETs. Simulations of these new strategies suggest reduced metal-induced gap states, negligible Schottky barrier height and small contact resistance (down to ~20 Ω·μm). Preliminary experimental results in developing Co <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> as a new semimetal contact material are also demonstrated.