The disclosure relates to methods of forming integrated circuit (IC) structures with a metal cap on a cobalt layer for source and drain regions of a transistor. An integrated circuit (IC) structure according to the disclosure may include: a semiconductor fin on a substrate; a gate structure over the substrate, the gate structure having a first portion extending transversely across the semiconductor fin; an insulator cap positioned on the gate structure above the semiconductor fin; a cobalt (Co) layer on the semiconductor fin adjacent to the gate structure, wherein an upper surface of the Co layer is below an upper surface of the gate structure; and a metal cap on the Co layer.