AVS 65th International Symposium & Exhibition
    Electronic Materials and Photonics Division Monday Sessions
       Session EM+AM+NS+PS-MoA

Paper EM+AM+NS+PS-MoA5
The Interconnect Resistivity Bottleneck

Monday, October 22, 2018, 2:40 pm, Room 101A

Session: Atomic Layer Processing: Selective-Area Patterning (Assembly/Deposition/Etching)
Presenter: Daniel Gall, Rensselaer Polytechnic Institute
Authors: D. Gall, Rensselaer Polytechnic Institute
T. Zhou, Rensselaer Polytechnic Institute
E. Milosevic, Rensselaer Polytechnic Institute
P.Y. Zheng, Micron Technology
Correspondent: Click to Email
The effective resistivity of conventional Cu interconnect lines increases by more than two orders of magnitude as their width is decreased from 30 to 6 nm. The resulting increase in signal delay and energy consumption limits downscaling of integrated circuits. This presentation will discuss the search for the most conductive metal solutions for narrow interconnect lines, focusing on three key aspects. (i) Electron surface scattering: In situ transport measurements on epitaxial Cu(001) layers with various monolayer cap-layers demonstrate specular electron surface scattering when the local surface density of states at the Fermi level is negligible, resulting in a considerable copper resistivity reduction. (ii) Alternative metals: The resistivity scaling at reduced dimensions is measured using epitaxial metal layers (Cu, Ag, W, Ta, Ru, Mo, Ni) and directly compared to results from classical transport models using first-principles electronic structure calculations. Multiple elemental metals are expected to be more conductive than Cu for polycrystalline lines <10 nm. (iii) Confined transport model: First-principles non-equilibrium transport simulations in combination with measurements of the resistivity vs roughness and dimensionality are used to develop a new model that accurately accounts for electron surface scattering in quantum-confined 1-D and 2-D conductors. This model will replace semiclassical models that fail to predict the resistivity <10 nm.