Embodiments of a deep trench capacitor are disclosed. In one example a plurality of deep trenches is located in a first region of a semiconductor wafer, the first region having a first conductivity type. A corresponding dielectric layer is located on a surface of each of the plurality of deep trenches, and a corresponding doped polysilicon filler is located within each of the dielectric layers. Dielectric-filled trenches are located between each of the dielectric layers and the surface of the semiconductor wafer.