Nanoscale characterization of a commercial sub-5nm FinFET device by Atom Probe Tomography

Atom probe tomography (APT), with its unique capability for atomic-scale, three-dimensional chemical mapping, offers a powerful solution for characterizing advanced semiconductor devices. In this work, we present a detailed APT-based nanoscale characterization of a commercially sourced 5 nm-technology node FinFET device. Site-specific specimen preparation was carried out with a focused ion beam to isolate regions of interest within the front-end-of-line and middle-of-line structures, enabling comprehensive analysis of critical device components. We report three key findings as well as discuss their potential implications on device performance, including: (i) pronounced B segregation to interfaces resulting in nanometer-sized clustering primarily along the perimeter of the SiGe source/drain regions; (ii) chemical purity and integrity of cobalt contacts, including localized oxidation and nitrogen ingress; and (iii) nanoscale composition distribution across the interfaces of the TiO x N y diffusion barrier layers. These observations are repeatedly observed in multiple datasets providing critical insights into dopant distribution, interconnect integrity, and barrier performance, all of which have direct implications for device reliability and performance in advanced technology nodes.