Monolayer-MoS<sub>2</sub> Stacked Nanosheet Channel with C-type Metal Contact
Yun-Yan Chung, Wei‐Sheng Yun, Bo-Jhih Chou, Chen-Feng Hsu, Shao-Ming Yu, Goutham Arutchelvan, Ming‐Yang Li, Tsung-En Lee, Bo-Jiun Lin, Chen-Yi Li, Aslan Wei, D. Mahaveer Sathaiya, Cheng-Ting Chung, San‐Lin Liew, Vincent Hou, Wen‐Hao Chang, Bo-Heng Liu, Chien-Wei Chen, Chien-Ying Su, Chi‐Chung Kei, Jin Cai, Chung-Cheng Wu, Jeff Wu, Tung-Ying Lee, Chao-Hsin Chien, Chao-Ching Cheng, Iuliana Radu
Abstract
This work demonstrates the first stacked nanosheet devices with monolayer MoS <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> channel after successful simultaneous release of 2 nanosheets. Two-stacked monolayer MoS <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> nanosheets with 50-nm width can be released free up to 150 nm, proving excellent mechanical properties of the channel material. Conformal gate stack deposition on the 2-stacked MoS <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> sheets is confirmed. To increase contact area, we introduce here ‘C-type’ wrap-around contact that contacts not only the edge but also the top and bottom side on the monolayer MoS <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> channels. For the first time, studies of gate stack and its impact on subthreshold swing, threshold voltage and hysteresis are presented on single nanosheet gate all around (GAA) devices. Unlike most reports in literature of depletion-mode monolayer MoS <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> devices, through appropriate process control and interface engineering we report here positive threshold voltage for NMOS devices.