Patent ID: 8258594

Claim:
An avalanche photodiode for detecting radiation, comprising: a) a semiconductor substrate having a top side and a bottom side opposite said top side, wherein the semiconductor substrate is doped according to a first doping type, b) an upper diode layer which is disposed in the semiconductor substrate on the top side, is doped according to a second doping type and is contactable, wherein the second doping type is opposed to the first doping type, c) a laterally restricted lower diode layer which is disposed in the semiconductor substrate between the upper diode layer and the bottom side of the semiconductor substrate and is doped according to the first doping type, d) an avalanche region which extends below the upper diode layer, and is adapted to undergo a radiation-generated avalanche breakdown when triggered by the radiation to be detected, e) a contacting layer which is disposed on the bottom side of the semiconductor substrate and is doped according to the first doping type, f) a laterally restricted quenching resistance layer which is disposed in the semiconductor substrate between the lower diode layer and the contacting layer and is doped according to the first doping type, wherein the quenching resistance layer is adapted to quench the radiation-generated avalanche breakdown in the avalanche region, and g) a depletion electrode which is disposed at least partially in a lateral manner with respect to the laterally restricted lower diode layer and is doped according to the second doping type, wherein (i) the upper diode layer protrudes with a side portion laterally beyond the laterally restricted lower diode layer and together with the protruding side portion forms the depletion electrode, (ii) the depletion electrode is adapted to deplete the semiconductor substrate laterally next to the laterally restricted lower diode layer, and (iii) the quenching resistance layer of the lower diode layer is shielded from the depletion electrode such that the quenching resistance layer is not depleted or is only partially depleted.