High On-State Current in Chemical Vapor Deposited Monolayer MoS2 nFETs With Sn Ohmic Contacts

Proving the device performance and process feasibility is imperative for the realization of two-dimensional (2D) semiconductor electronics. In this work, we have successfully adopted Tin (Sn) as the Ohmic contact metal to monolayer molybdenum disulfide (MoS2) grown by chemical vapor deposition (CVD) and demonstrated superior short channel n-type field effect transistor (nFET) performance reaching an ON-current of 480 mu A/mu m and keeping the OFF-current below0.1 nA/mu m at V-DS = 1 V. These efforts are close to the low power specification of Si transistors in the metrics of International Roadmap forDevices and Systems (IRDS). The performance improvement could be attributed to the re-melting behavior of Sn metal. We suggest that the Sn deposited at lower temperatures could reduce the formation of interfacial defects caused by heat, and high-melting-point capping metal also could assist the re-melting phenomenon of underlying Sn contact layer. These process modifications are helpful to form smooth Sn coverage on MoS2, thereby reducing the contact resistance to 0.84 k Omega center dot mu m. This work provides a practical pathway to form low-resistance metal contact on 2D semiconductors for performance improvement.

Automated summary

By adopting Sn metal as the Ohmic contact metal on MoS2 and using high-melting-point capping metal, the performance of 2D semiconductor devices has been improved, providing a practical pathway to form low-resistance metal contacts on 2D semiconductors.