An integrated structure comprises a substrate with a first dielectric layer and a second dielectric cap layer disposed thereon in sequence, a metal gate transistor with a high-k gate dielectric layer on the substrate, a gate electrode embedded within the first dielectric layer and a source/drain within the substrate, a first metal contact penetrating the first dielectric layer and being in direct contact with the source/drain and a through-silicon via penetrating the second dielectric cap layer, the first dielectric layer and the substrate.