| 摘要 |
PROBLEM TO BE SOLVED: To enhance the resolution of image by using a high resistant silicon base having a high specific resistance as semiconductor substrate. SOLUTION: A semiconductor substrate 1 is formed of, for example, P-type silicon substrate having a high resistance. When a sample 8 is put into a vessel 7, a potential according to pH of the sample 8 making contact with a sensing part 4 is generated on the surface of a Si3 N4 film 6. A bias voltage is applied between a counter electrode 10 and an ohmic electrode 11 to form a depletion layer 3, and a probe light 14 is emitted to the semiconductor substrate 1 which scanning in X, Y directions. A photoelectric current is generated, and this current quantity corresponds to pH of the sample 8 making contact with the sensing part 4. A two-dimensional image showing pH distribution is provided by the position signal (X, Y) and the current quantity. Since a P-type silicon substrate having a high resistance is used as the semiconductor substrate 1, the distance of the optical carrier reaching the depletion layer 3 is shortened because of the thick depletion layer 3 and the thin P layer 2, the width of lateral diffusion of the optical carrier is reduced, and the spatial resolution is improved. |
