| 摘要 |
PURPOSE:To improve the light receiving efficiency of a semiconductor photodetector by employing a reverse conductive type low density impurity implanted region which is formed to surround the partial region of a conductive type low impurity density semiconductor substrate and exists within diffused distance of conductive carrier at the shortest distance from all points on the surface of the region. CONSTITUTION:Part on an N type semiconductor substrate 1 is exposed to surround a P type impurity implanted region 3 in a photoreceiving surface. Since the exposed region is certainly low impurity density, its photoreceiving efficiency is excellent. The relationship between the region 3 and the region exposed at the substrate 2 is, at any point of the region, specified such that the shortest distance to the region 3 falls within the diffused distance of conductive carrier. The distance between the side faces 7 and 8, i.e., the width D is suitably selected, but the peripheral length of the region 3 can be shortened when it is selected to twice or slightly smaller than that at the diffused distance of the carrier, and preferable to reduce the contacting capacity. Since the region 3 and the substrate 2 can transmit the light, the light can be incident to the substrate 2 disposed under the region 3 without large attenuation if the wavelength of the light is suitable, thereby contributing to the improvement in the photoreceiving efficiency. |
