Patent ID: 8716821

Claim:
A semiconductor device, comprising: a substrate comprising a semiconductor having a first conductivity type; a photodiode, comprising: a buried collection region formed by a bandgap well, said buried collection region being disposed in said substrate; said buried collection region having said first conductivity type, said buried collection region having a net average doping density at least a factor of ten less than a net average doping density of a region in said substrate above and contacting said buried collection region and at least a factor of ten less than a net average doping density of said substrate below said buried collection region within 100 microns of said buried collection region; and a cathode having a second conductivity type opposite from said first conductivity type, said cathode extending from a top surface of said substrate to said buried collection region, making electrical connection to said buried collection region, so that a lateral area of said cathode is less than a lateral area of said buried collection region.