The present disclosure provides a semiconductor structure, including: a semiconductor device layer including a first surface and a second surface, wherein the first surface is at a front side of the semiconductor device layer, and the second surface is at a backside of the semiconductor device layer; an insulating layer above the second surface of the semiconductor device; and a through-silicon via (TSV) traversing the insulating layer. Associated manufacturing methods of the same are also provided.

The present disclosure describes a method to form a stacked semiconductor device with power rails. The method includes forming the stacked semiconductor device on a first surface of a substrate. The stacked semiconductor device includes a first fin structure, an isolation structure on the first fin structure, and a second fin structure above the first fin structure and in contact with the isolation structure. The first fin structure includes a first source/drain (S/D) region, and the second fin structure includes a second S/D region. The method also includes etching a second surface of the substrate and a portion of the first S/D region or the second S/D region to form an opening. The second surface is opposite to the first surface. The method further includes forming a dielectric barrier in the opening and forming an S/D contact in the opening.