ION CONCENTRATION SENSOR

WIPO Patent Application WO/2017/090322

A1

Disclosed is an ion concentration sensor wherein both improved output SN ratio and high responsiveness are achieved. In an ion sensor (100), a sensing unit (1) accumulates electrons as signal charges, said electrons having been injected from an n-type substrate (21) via a p well (22). The p well (22) is laminated on the n-type substrate (21). The p-well (22) positioned between the sensing unit (1) and the n-type substrate (21) has impurity concentration distribution, and the maximum value C1 of the impurity concentration in the p-well (22) is 0