Interdigitated capacitor in split-gate flash technology

Abstract

The present disclosure relates to an inter-digitated capacitor that can be formed along with split-gate flash memory cells and that provides for a high capacitance per unit area, and a method of formation. In some embodiments, the inter-digitated capacitor has a well region disposed within an upper surface of a semiconductor substrate. A plurality of trenches vertically extend from the upper surface of the semiconductor substrate to positions within the well region. Lower electrodes are arranged within the plurality of trenches. The lower electrodes are separated from the well region by a charge trapping dielectric layer arranged along inner-surfaces of the plurality of trenches. A plurality of upper electrodes are arranged over the semiconductor substrate at locations laterally separated from the lower electrodes by the charge trapping dielectric layer and vertically separated from the well region by a first dielectric layer.