| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that the amount of a saturation signal charge decreases and the inclination of knee characteristics cannot be reduced fully only by the control of the impurity concentration profile of the P-type region when the impurity concentration profile of a P-type region is changed for decreasing the inclination of the knee characteristics while the inclination of the knee characteristics of a photoelectric conversion element in vertical-type overflow drain structure are expressed by the function of an impurity concentra tion profile such as the impurity concentration and thickness of the P-type region for forming a VOD barrier. SOLUTION: Directly below the center part of an N-type region 103 of a photoelectric conversion element 201, the impurity concentration of a P-type region 122 (the first barrier region) that is buried into an N-type silicon substrate 101 for forming is set higher than that of other P-type regions 102 (the second barrier region), or the thickness of the P-type region 122 is set thicker than that of the P-type region 102. The inclination of the knee characteristics can be reduced without increasing the influence of a P+-channel stopper 105 and a P-type region 107 to a VOD barrier in the P-type region 122 and reducing the amount of saturation signal charge, thus increasing the dynamic range.
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