Semiconductor capacitor for stacked pixel

Abstract

Various embodiments of the present disclosure are directed towards an image sensor including a first integrated circuit (IC) die stacked with a second IC die. The first IC die includes a plurality of photodetectors disposed within a first substrate. The second IC die includes a plurality of pixel transistors and a semiconductor capacitor disposed on a second substrate. The semiconductor capacitor includes a first capacitor electrode, a capacitor dielectric layer, and a doped capacitor region. The first capacitor electrode overlies the second substrate and comprises a protrusion disposed in the second substrate. The capacitor dielectric layer is disposed between the first capacitor electrode and the second substrate. The doped capacitor region is disposed within the second substrate and underlies the first capacitor electrode. The plurality of photodetectors, the plurality of pixel transistors, and the semiconductor capacitor define a pixel.