Effective wet cleaning for high-performance monolayer MoS₂ transistor fabrication using N-methyl-2-pyrrolidone

Kristan Bryan Simbulan^1*, Po-Chun Chen¹, Chih-Pin Lin², Chuan-Jie Hong³, Chih-Hao Yang³, Yun-Yan Lin¹, Ming-Yang Li⁴, Lain-Jong Li⁵, Tung-Yuan Yu⁶, Chun-Jung Su⁶, Kai-Shin Li⁶, Yuan-Liang Zhong³, Tuo-Hung Hou², Yann-Wen Lan¹

¹Department of Physics, National Taiwan Normal University, Taipei, Taiwan
²Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, Hsinchu, Taiwan
³Department of Physics and Center for Nanotechnology, Chung Yuan Christian University, Chungli, Taiwan
⁴Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
⁵Physical Sci. and Eng., King Abdullah University of Sci. and Technology, Thuwal, Saudi Arabia
⁶National Nano Device Laboratories, National Applied Research Laboratories, Hsinchu, Taiwan

* Presenter:Kristan Bryan Simbulan, email:80641005s@ntnu.edu.tw

The strong susceptibility of two-dimensional semiconductors, such as MoS₂, to various molecular adsorbates during fabrication unfavourably affects device performance. To ensure high device yield, uniformity, and performance, wet chemical cleaning has long been used in the semiconductor industry to remove undesirable surface contaminations, native oxides, and adsorbates from the surface of Si wafers. However, a similarly effective surface cleaning technique has not yet been fully developed specifically for two-dimensional materials; hence, we propose a wet chemical cleaning strategy for MoS₂ using N-Methyl-2-pyrrolidone (NMP). We found that NMP does not only preserve the intrinsic properties of monolayer MoS₂ but, at the same time, significantly improves the performance of monolayer MoS₂ field-effect transistors (FETs). Moreover, a contact resistance of 15 kΩ-μm, field-effect mobility of 15.5 cm²/V-s, and an average on-off current ratio of 10⁸ were recorded. This study presents a new yet simple strategy toward a highly manufacturable cleaning process for MoS₂ FETs.

Keywords: Wet Chemical Cleaning, Monolayer MoS₂ Device, N-Methyl-2-Pyrrolidone , MoS₂ Field Effect Transistor, Monolayer MoS₂ Fabrication