| 摘要 |
A first impurity region 2 of a reverse conductivity type configuring a photoelectric conversion element and a buried channel region 3 of a reverse conductivity type configuring an element for transferring signal charges are formed in a principal surface portion of a semiconductor substrate 1 of one conductivity type, and a first insulating film 4 is formed on the semiconductor substrate. Then, a readout electrode 5 is formed in an area including a region on the buried channel region, and a second insulating film 6 for covering the readout electrode is formed. After that, a side wall forming film 7 a is formed and a selective etching is carried out based on an etching selectivity ratio, thereby forming side walls 7 on side faces of the readout electrode with the second insulating film interposed therebetween. Then, ion implantation using the readout electrode and the side walls as masks is carried out to form a second impurity region 8 of one conductivity type in a self-alignment manner, followed by removal of the side walls. It is possible to obtain a reduced dark current, a stabilized readout voltage, etc., without decreasing the sensitivity, and to retain a sufficient thickness of the second insulating film.
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