The current disclosure describes techniques for forming a low resistance junction between a source/drain region and a nanowire channel region in a gate-all-around FET device. A semiconductor structure includes a substrate, multiple separate semiconductor nanowire strips vertically stacked over the substrate, a semiconductor epitaxy region adjacent to and laterally contacting each of the multiple separate semiconductor nanowire strips, a gate structure at least partially over the multiple separate semiconductor nanowire strips, and a dielectric structure laterally positioned between the semiconductor epitaxy region and the gate structure. The first dielectric structure has a hat-shaped profile.