US Patent 10217889 Clamped avalanche photodiode

An avalanche photodiode device operated in Geiger-mode, the device comprising a P-N junction formed on a substrate with a first semiconductor region and a second semiconductor region with an anode and cathode. The device further comprising a third semiconductor region, the third semiconductor region in physical contact with the second region, not in physical contact with the first region, and being the same semiconductor-type as the first semiconductor region. Additionally comprising a diode on the second semiconductor region and having a turn-on voltage than the P-N junction.