Backside-illuminated photodetector

摘要

The present invention provides a back illuminated photodetector having a sufficiently small package as well as being capable of suppressing the scattering of to-be-detected light. A back illuminated photodiode 1 comprises an N-type semiconductor substrate 10 , a P⁺-type doped semiconductor region 11 , a recessed portion 12 , and a coating layer 13 . In the surface layer on the upper surface S 1 side of the N-type semiconductor substrate 10 is formed the P⁺-type doped semiconductor region 11 . In the rear surface S 2 of the N-type semiconductor substrate 10 and in an area opposite the P⁺-type doped semiconductor region 11 is formed the recessed portion 12 that functions as an incident part for to-be-detected light. Also, on the rear surface S 2 is provided the coating layer 13 for transmitting to-be-detected light that is made incident into the recessed portion 12 . The coating layer 13 is here arranged in such a manner that the portion provided on the recessed portion 12 is sunk lower than the portion provided on the outer edge portion 14 of the recessed portion 12.