| 摘要 |
PROBLEM TO BE SOLVED: To improve durability of a photodetector for high-energy beams. SOLUTION: A photodetector includes a silicon oxide layer whose thickness od 3 to 10 nm formed on a first conductive silicon substrate, a first conductivity-type depletion blocking region formed just under the silicon oxide film, and a second conductivity-type charge accumulation region formed under the depletion blocking region. Since the oxide film is thin, electron-hole pairs are reduced which are generated in the oxide film by irradiation with high-energy beams. Furthermore, it is expected that the electron moving range becomes narrow and the probability for electrons to be recombined with holes near an interface becomes high. Namely, the holes near the interface are reduced. Moreover, since the depletion blocking region of the same conductivity type as that of the substrate is fixed to a substrate potential, the change of potential of the interface is suppressed. Accordingly, since signal charges being trapped in the valley of the potential on the interface becomes fewer, it is expected that quantum efficiency will not be reduced much, even after irradiation. COPYRIGHT: (C)2005,JPO&NCIPI |
