Patent ID: 7332751

Claim:
A rear-illuminated-type photodiode array comprising: (a) a first-electroconductive-type n-type InP semiconductor substrate; (b) a first-electroconductive-type n-electrode that: (b1) is disposed at the rear side of the semiconductor substrate; and (b2) has a plurality of openings arranged one- or two-dimensionally; (c) an antireflective coating at each of the openings of the first-electroconductive-type electrode; (d) a first-electroconductive-type InGaAs absorption layer that: (d1) is disposed at the front-face side of the semiconductor substrate; and (d2) has an absorption edge wavelength of λgr; (e) a leakage-lightwave-absorbing n-type InGaAs layer that: (e1) is disposed on the absorption layer; and (e2) has an absorption edge wavelength, λga, longer than the absorption edge wavelength, λgr, of the absorption layer (λga>λgr); (f) a plurality of second-electroconductive-type p-regions that: (f1) penetrate through the leakage-lightwave-absorbing layer from the top surface and extend at least partially into the absorption layer; and (f2) are arranged one- or two-dimensionally at positions coinciding with those of the antireflective coatings at the opposite side; and (g) a second-electroconductive-type p-electrode on the top surface of each of the second-electroconductive-type, regions.