The present disclosure relates to an integrated chip having an inter-digitated capacitor, and an associated method of formation. In some embodiments, the integrated chip has a plurality of upper electrodes separated from a substrate by a first dielectric layer. A plurality of lower electrodes vertically extend from between the plurality of upper electrodes to locations embedded within the substrate. A charge trapping dielectric layer is arranged between the substrate and the plurality of lower electrodes and between the plurality of upper electrodes and the plurality of lower electrodes. The charge trapping dielectric layer has a plurality of discrete segments respectively lining opposing sidewalls and a lower surface of one of the plurality of lower electrodes.