Device structures and fabrication methods for a field-effect transistor. A first dielectric spacer adjacent to a sidewall of a gate placeholder structure. A contact placeholder structure is formed adjacent to the first dielectric spacer such that the first dielectric spacer is arranged laterally between the gate placeholder structure and the contact placeholder structure. The contact placeholder structure and the first dielectric spacer are recessed to open a space over the contact placeholder structure and the first dielectric spacer. A second dielectric spacer is formed in the space adjacent to the sidewall of the gate placeholder structure and over the first dielectric spacer.