| 摘要 |
PURPOSE:To enhance the effect of avalanche multiplying action, by providing a special lens, which enhances the multiplying action of carriers, at a light receiving window part on the side of a substrate of a semiconductor photodetector, effectively condensing light into a light absorbing region, and generating many carriers. CONSTITUTION:A p-type InP layer 2, an n-type InP layer 3, which is to become an avalanche region, and an n-type In1-xGaxAs layer 4, which is to become a light absorbing region, and in which a thickness is 2-3 mum, carrier concentration is 1X10<16>cm<-3> and x=0.53, are sequentially formed on a p-type InP semiconductor single crystal substrate 1. A p-side electrode 5 is provided and a light receiving window part 9 is formed. An n-side electrode 6 is provided. A spherical lens 7 is bonded to the light receiving window part 9 by using a resin 8. The light, which is condensed through the spherical lens 7, is transmitted through the substrate 1 and the InP layers 2 and 3 and absorbed in the layer 4 in the light absorbing region. The generation of many carriers is accelerated by the action of the spherical lens 1. When a depletion layer reaches the light absorbing region by a reverse bias, the carriers are conveyed into the avalanche region and further multiplied.
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