Statistical limits of contact resistivity due to atomistic variation in nanoscale contacts

Using large-scale quantum transport simulations, we calculate the intrinsic variability of contact resistivity in scaled Si devices due to atomistic variation. We further demonstrate that tunneling resistance and metal band structure mismatch each account for approximately half of the increase in contact resistivity above fundamental lower bounds. The results suggest that worsening variability must be counteracted by barrier height modulation to meet targets in future technology nodes.