Patent ID: 7605406

Claim:
A rear-illuminated-type photodiode array comprising: (a) a first-electroconductive-type semiconductor substrate; (b) a first-electroconductive-type electrode that: (b1) is at a 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 absorption layer that: (d1) is at a front-face side of the semiconductor substrate; and (d2) has an absorption edge wavelength of λ gr ; (e) a leakage-lightwave-absorbing layer that: (e1) is over the entire absorption layer; and (e2) has an absorption edge wavelength, λ ga , longer than the absorption edge wavelength, λ gr , of the absorption layer (λ ga >λ gr ); (f) a plurality of lightwave receiving parts comprising: (f1) a plurality of second-electroconductive-type regions that: (f11) penetrate through the leakage-lightwave-absorbing layer from the top surface and extend partially into the absorption layer; and (f12) are arranged one- or two-dimensionally at positions at the top surface so as to be substantially aligned with and opposite positions of the antireflective coatings; and (g) a second-electroconductive-type electrode provided on the top surface of each of the second-electroconductive-type regions, the array further comprising a window layer that is disposed between the absorption layer and the leakage-lightwave-absorbing layer, the window layer having an absorption edge wavelength, λ gw , shorter than the absorption edge wavelength, λ gr , of the absorption layer (λ gw <λ gr ), and the second-electroconductive-type regions penetrating through the window layer.