| 摘要 |
PURPOSE:To prevent the recombination of electrons and holes formed by light energy, and to improve and stabilize photo-sensitivity by shaping an isolation region having a conductivity type reverse to a semiconductor substrate and high concentration onto the side face of a light-receiving region formed onto a main surface. CONSTITUTION:An isolation region 9 having a reverse conductivity type and high concentration is shaped onto the side face of a light-receiving region. When negative potential is applied to an emitter electrode 6 and positive potential to a collector electrode 7, depletion layers are formed in a base region 2 and in an N-type region near the base region 2, and a photo-transistor is brought to a nonconductive state. When beams are projected from the first main surface side under the state, electrons and hole pairs are shaped. Holes as minority carriers in the N-type region in a semiconductor substrate 1 as the light-receiving region are transferred by a diffusion, and one part thereof reaches to the depletion layers. Holes are accelerated by an electric field and injected into the base region 2, and turned into substantial base currents. Holes, which are optically pumped and shifted in the direction of a collector region 4 and the direction of, a chip side-face, are reflected by built-in potential shaped between N-N<+> regions, and the greater part thereof are changed into base currents.
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