Patent ID: 8780248

Claim:
An image pickup apparatus comprising: a plurality of pixels; wherein each of the plurality of pixels includes a photoelectric conversion unit, and an amplifier element configured to output a signal based on charge generated by the photoelectric conversion unit; wherein, within an electric path between the photoelectric conversion unit and an input node of the amplifier element, there are disposed a first holding unit, a second holding unit disposed in a subsequent stage of the first holding unit, a first transfer unit configured to transfer charge to the first holding unit, a second transfer unit configured to transfer charge of the first holding unit to the second holding unit, and a third transfer unit configured to transfer charge of the second holding unit; wherein the first holding unit includes a first conductive-type first semiconductor region which holds charge; wherein the second holding unit includes a first conductive-type second semiconductor region which holds charge; and wherein impurity concentration of the first semiconductor region is lower than impurity concentration of the second semiconductor region.