Imaging device

Patent Granted Almost in the center of the light-receiving surface of an embedded photodiode (31), a floating diffusion (331) is formed and the gate electrode of a transfer transistor (32) is so disposed as to surround it. The impurity concentration (or depth) in the p+-type semiconductor region, n-type semiconductor region or p-type well region of the photodiode (31) is so inclined from the periphery toward the center as to form a potential gradient inclined downward from the periphery toward the center when applying a proper bias voltage to a pn junction.