Computational Screening and Multiscale Simulation of Barrier-Free Contacts for 2D Semiconductor pFETs

Low-resistance p-type contacts to two-dimensional (2D) semiconductors remains a critical challenge towards the industrial application of 2D channel materials in advanced logic technology. To address this challenge, we computationally screen and identify designs for ultralow-resistance p-type contacts to 2D semiconductors such as WSe2 by combining ab initio density-functional-theory (DFT) and quantum device simulations. Two new contact strategies, van der Waals metallic contact (such as 1H-NbS2), and bulk semimetallic contact (such as Co3 Sn2 S2), are identified as realistic pathways to achieving Schottky-barrier-free and low-contact-resistance p-type contacts for 2D semiconductor pFETs. Simulations of these new strategies suggest reduced metal-induced gap states, negligible Schottky barrier height and small contact resistance (down to 20 Ω·μm). Preliminary experimental results in developing Co3 Sn2 S2 as a new semimetal contact material are also demonstrated.