A semiconductor structure includes a first source/drain (S/D) epitaxial feature, a second S/D epitaxial feature adjacent to the first S/D epitaxial feature, an insulating structure between the first and the second S/D epitaxial features, and a shared S/D contact over top surfaces of the first and the second S/D epitaxial features. A center portion of the shared S/D contact is directly between a side surface of the first S/D epitaxial feature and a side surface of the second S/D epitaxial feature. The center portion is directly above the insulating structure. The semiconductor structure further includes a backside via penetrating through the insulating structure to directly land on a bottom surface of the center portion.