Improved Contacts to MoS 2 Transistors by Ultra-High Vacuum Metal Deposition

The scaling of transistors to sub-10 nm dimensions is strongly limited by their contact resistance (RC). Here we present a systematic study of scaling MoS2 devices and contacts with varying electrode metals and controlled deposition conditions, over a wide range of temperatures (80 to 500 K), carrier densities (1012 to 1013 cm–2), and contact dimensions (20 to 500 nm). We uncover that Au deposited in ultra-high vacuum (∼10–9 Torr) yields three times lower RC than under normal conditions, reaching 740 Ω·μm and specific contact resistivity 3 × 10–7 Ω·cm2, stable for over four months. Modeling reveals separate RC contributions from the Schottky barrier and the series access resistance, providing key insights on…

• SU
  Stanford University
• SS
  Stanford SystemX Alliance
• DO
  Division of Emerging Frontiers in Research and Innovation

  Award: EFRI-1542883
• AF
  Air Force Office of Scientific Research

  Award: FA9550-14-1-0251