Various embodiments of the present disclosure are directed towards a pixel sensor including a dummy vertical transistor structure underlying a photodetector. The pixel sensor includes a substrate having a front-side surface opposite a back-side surface. The photodetector is disposed within the substrate. A deep trench isolation (DTI) structure extends from the back-side surface of the substrate to a first point below the back-side surface. The DTI structure wraps around an outer perimeter of the photodetector. The dummy vertical transistor structure is laterally spaced between inner sidewalls of the DTI structure. The dummy vertical transistor structure includes a dummy vertical gate electrode having a dummy conductive body and a dummy embedded conductive structure. The dummy embedded conductive structure extends from the front-side surface of the substrate to a second point vertically above the first point and the dummy conductive body extends along the front-side surface of the substrate.