Patent ID: 7365380

Claim:
A photoelectric conversion device comprising a semiconductor substrate of first conductive type; a photoelectric conversion element comprising a first semiconductor region of a second conductive type and a second semiconductor region of said first conductive type forming a PN junction with said first semiconductor region; and a transfer MOS transistor for transferring charge stored in said second semiconductor region, wherein said first semiconductor region includes at least a first impurity region, a second impurity region provided between said first impurity region and a surface of said substrate, a third impurity region provided between said second impurity region and the surface of said substrate, and a fourth impurity region provided between said third impurity region and the surface of said substrate, and each of the impurity regions having an impurity concentration peak in a depth direction, and a concentration C 1 corresponding to a first impurity concentration peak in said first impurity region, a concentration C 2 corresponding to a second impurity concentration peak in said second impurity region, a concentration C 3 corresponding to a third impurity concentration peak in said third impurity region, and a concentration C 4 corresponding to a fourth impurity concentration peak in said fourth impurity region satisfy the following relationship: C2=C3<C4<C1; and wherein said second semiconductor region includes a plurality of semiconductor regions and a part of each of said plurality of semiconductor regions of said second semiconductor region is disposed under a part of a gate of said transfer MOS transistor.