Wafer-Scale Bi-Assisted Semi-Auto Dry Transfer and Fabrication of High-Performance Monolayer CVD WS<sub>2</sub> Transistor
Ming‐Yang Li, Ching-Hao Hsu, Shin‐Wei Shen, Ang‐Sheng Chou, Yuxuan Lin, Chih‐Piao Chuu, Ning Yang, Sui-An Chou, Lin-Yun Huang, Chao-Ching Cheng, Wei-Yen Woon, Szuya Sandy Liao, Chih‐I Wu, Lain‐Jong Li, Iuliana Radu, H.‐S. Philip Wong, Han Wang
Abstract
A novel wafer-scale semi-automated dry transfer process for monolayer (1L) CVD WS <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> was developed utilizing the weakly coupled interface between semimetal (Bi) and two-dimensional (2D) semiconductor (WS <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> ). Bi semimetal serves as a gently adhesive transfer template for 2D materials, introducing minimal additional defects during the transfer process. Based on 2D materials processed using this new transfer method, semimetal-contacted (Bi and Sb) monolayer CVD WS <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> nFETs were further demonstrated at wafer scale. Our CVD 1L WS <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> nFETs fabricated using semimetal-assisted transfer with semimetal (Bi and Sb) contacts show record high on-current of 250 µA/µm and 243 µA/µm at V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</inf> = 1 V, and record low contact resistance of 0.63 kΩ•µm and 0.73 kΩ•µm, respectively.