A semiconductor structure includes a trench capacitor, a stacked capacitor, a first electrode plate, and a second electrode plate. The trench capacitor is located in a substrate, in which the trench capacitor has a first conductive structure and a first dielectric structure in contact with the first conductive structure. The stacked capacitor has a second conductive structure and a second dielectric structure in contact with the second conductive structure, in which the stacked capacitor is at least partially aligned with the trench capacitor in an axis vertical to a top surface of the substrate, and the first and second conductive structures are electrically connected. The trench capacitor and the stacked capacitor are electrically connected in parallel between the first and second electrode plates.