PINNED PHOTODIODE OF IMAGE SENSOR, AND ITS MANUFACTURE

摘要

PROBLEM TO BE SOLVED: To provide a pinned photodiode which can increase the depth of a depletion layer further more as compared with a prior art so as to get very high photosensitivity. SOLUTION: The pinned photodiode of an image sensor includes a first conductivity type of semiconductor layer, an at least two layers of first doping regions which are made within the above semiconductor layer and are stacked, with the ions of second conductivity type of impurities implanted two times at least with mutually different energy, and a first conductivity type of second doping region which is made between the top of the uppermost first doping region in the two layers of first doping regions and the surface of the above semiconductor layer and is made with its area larger than the area of the above doping region and whose one region is made on the above semiconductor layer.