| 摘要 |
PROBLEM TO BE SOLVED: To provide an ion sensor having highly integrated fine cells of 10 um or less in which the area of a sensing part in an ion concentration sensor is increased.SOLUTION: The ion sensor is a photodiode type ion concentration sensor making the most of a CCD type image sensor. In a light-receiving area 5, each of a photodiode part (sensing part 1) and a vertical transfer part 4 is formed by ion implantation and photolithography in a P well 22 formed on an N-type substrate 21. The photodiode part constitutes the sensing part 1. When electron injection is performed from the N-type substrate 21, the potential of the N-type substrate 21 is changed before injection. Therefore, to ensure that no electric charge will be injected into N-type areas (e.g., the vertical transfer part 4, horizontal transfer part 7) other than the photodiode part formed in the P well 22, a portion where the photodiode part is formed and other portions of the P well 22 have different dopant concentrations.SELECTED DRAWING: Figure 1 |
