Various embodiments of the present disclosure are directed towards an image sensor. The image sensor includes a photodetector disposed in a semiconductor substrate. An interlayer dielectric (ILD) structure is disposed on a first side of the semiconductor substrate. A storage node is disposed in the semiconductor substrate and spaced from the photodetector, where the storage node is spaced from the first side by a first distance. A first isolation structure is disposed in the semiconductor substrate and between the photodetector and the storage node, where the first isolation structure extends into the semiconductor substrate from a second side of the semiconductor substrate that is opposite the first side, and where the first isolation structure is spaced from the first side by a second distance that is less than the first distance.