PIXEL AND CIRCUIT DESIGN FOR IMAGE SENSORS WITH HOLE-BASED PHOTODIODES

摘要

In order to reduce dark current and pixel readout noise in an image sensor, pixels may include a p-type hole-based pinned photodiode. Charge stored in the p-type pinned photodiode may be transferred to a p-type floating diffusion (FD) node and read out by pixel circuitry that uses p-channel metal oxide-semiconductor field-effect transistors (p-channel MOSFET). Additionally, the pixel circuitry may be split across multiple wafers that are connected by metal interconnect layers. This arrangement may enable the pixel photodiode to have a larger size than if all of the pixel circuitry was in a single wafer.