Some embodiments relate to an integrated chip including a semiconductor substrate and a pixel array comprising a plurality of photodetectors in the semiconductor substrate. The pixel array further comprises a plurality of transistors on a frontside of the semiconductor substrate. A backside ground (BSGD) structure extends into a backside of the semiconductor substrate, opposite the frontside, and further surrounding the pixel array along a periphery of the pixel array. The BSGD structure has a first sloped sidewall extending from a bottom surface of the BSGD structure that is recessed into the semiconductor substrate.