Patent ID: 9190551
Filing Date: 2015-11-17
Classification: H01L,Y02E

Abstract:
1. A photodiode comprising: a silicon substrate comprised of a semiconductor of a first conductivity type and having a first principal surface and a second principal surface opposed to each other, wherein an avalanche photodiode composed of a pn junction between a semiconductor region of the first conductivity type having a higher impurity concentration than the silicon substrate and a semiconductor region of a second conductivity type is arranged on a first principal surface side of the silicon substrate, wherein on a second principal surface side of the silicon substrate, an accumulation layer of the first conductivity type having a higher impurity concentration than the silicon substrate is formed and an irregular asperity is formed in at least a region opposed to the avalanche photodiode, wherein the region opposed to the avalanche photodiode in the second principal surface of the silicon substrate is optically exposed, and wherein the first principal surface constitutes a light incident surface, light incident from the first principal surface travels in the silicon substrate, the photodiode being a front-illuminated type.