Control of Growth Morphology of Deposited fcc Metals through Tuning Substrate-Metal Interactions

Precise control over thin film morphology is critical for optimizing material properties across diverse technological applications, as growth mode─whether 2D layer-by-layer or 3D island formation─determines key functional properties such as electrical conductivity in Complementary Metal-Oxide-Semiconductor (CMOS) interconnects and catalytic activity, where island distribution and size dictate performance. To explore the role of substrate interactions on metal morphology, we present extensive kinetic Monte Carlo simulations on six fcc metals growing in the (111) direction: Ag, Au, Cu, Ni, Pd, and Pt. Our simulations enable screening and evaluation of growth modes under homoepitaxial scenarios and propose morphology control strategies through substrate-metal interaction strength variation, modeled by modifying activation energies for atomic migration, combined with thermal vacuum annealing within typical back end of line (BEOL) integration thermal budget. Our results demonstrate that substrate interaction strength modulation effectively promotes either island formation or layer-by-layer growth, overcoming limitations in achieving large flat surface areas. Au, Pd, and Pt exhibit the highest sensitivity to interaction strength variations, followed by Ag, showing that strongly interacting substrates decrease the root-mean-square (RMS) roughness, substrate exposure, island number, and aspect ratios, with moderate increases in flat surface areas and atomic coordination numbers. Additionally, interconnect-relevant metrics improve through thermal vacuum annealing particularly with strong metal-substrate interactions, reducing surface roughness, achieving larger flat areas, merging/smoothing islands, and decreasing defect density. We highlight not only the role of intrinsic metal migration barriers but also the critical contribution of metal coordination number. Our results can support the selection of alloy components for target applications: Ni, Ag, Pd, and Pt may be useful alloyed with other metals for interconnect applications, particularly given that Pd and Pt need to be combined with cheaper metals to leverage their beneficial properties while maintaining cost-effectiveness.