METHOD AND APPARATUS FOR DARK CURRENT AND HOT PIXEL REDUCTION IN ACTIVE PIXEL IMAGE SENSORS

摘要

A method of operating an imager pixel that includes the act of applying a relatively small voltage on the gate of a transfer transistor during a charge acquisition period. If a small positive voltage is applied, a depletion region is created under the transfer transistor gate, which creates a path for dark current electrons to be transferred to a pixel floating diffusion region. The dark electrons are subsequently removed by a pixel reset operation. If a small negative voltage is applied to the transfer gate, electrons that would normally create dark current problems will instead recombine with holes thereby substantially reducing dark current.