Ultrascaled Contacts to Monolayer MoS2 Field Effect Transistors

Thomas F Schranghamer; Najam U Sakib; Muhtasim Ul Karim Sadaf; Shiva Subbulakshmi Radhakrishnan; Rahul Pendurthi; Ama Duffie Agyapong; Sergei P Stepanoff; Riccardo Torsi; Chen Chen; Joan M Redwing; Joshua A Robinson; Douglas E Wolfe; Suzanne E Mohney; Saptarshi Das

doi:10.1021/acs.nanolett.3c00466

Ultrascaled Contacts to Monolayer MoS₂ Field Effect Transistors

Nano Lett. 2023 Apr 26;23(8):3426-3434. doi: 10.1021/acs.nanolett.3c00466. Epub 2023 Apr 14.

Authors

Thomas F Schranghamer¹, Najam U Sakib¹, Muhtasim Ul Karim Sadaf¹, Shiva Subbulakshmi Radhakrishnan¹, Rahul Pendurthi¹, Ama Duffie Agyapong², Sergei P Stepanoff^{2

3}, Riccardo Torsi², Chen Chen⁴, Joan M Redwing^{2

4

5}, Joshua A Robinson², Douglas E Wolfe^{1

2

3}, Suzanne E Mohney^{2

5}, Saptarshi Das^{1

2

5}

Affiliations

¹ Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802, United States.
² Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States.
³ Applied Research Laboratory, Pennsylvania State University, University Park, Pennsylvania 16802, United States.
⁴ 2D Crystal Consortium Materials Innovation Platform, Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, United States.
⁵ Department of Electrical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States.

PMID: 37058411
DOI: 10.1021/acs.nanolett.3c00466

Abstract

Two-dimensional (2D) semiconductors possess promise for the development of field-effect transistors (FETs) at the ultimate scaling limit due to their strong gate electrostatics. However, proper FET scaling requires reduction of both channel length (L_CH) and contact length (L_C), the latter of which has remained a challenge due to increased current crowding at the nanoscale. Here, we investigate Au contacts to monolayer MoS₂ FETs with L_CH down to 100 nm and L_C down to 20 nm to evaluate the impact of contact scaling on FET performance. Au contacts are found to display a ∼2.5× reduction in the ON-current, from 519 to 206 μA/μm, when L_C is scaled from 300 to 20 nm. It is our belief that this study is warranted to ensure an accurate representation of contact effects at and beyond the technology nodes currently occupied by silicon.

Keywords: interfaces; scaling; semiconductors; transistors; two-dimensional materials.