The characteristics of laser-induced electrical failure in biased silicon avalanche photodiodes have been observed. The samples were RCA reach-through avalanche photodiodes with antireflection coatings. They were biased at typical operating voltages during irradiation. The laser source was a Q-switched 1064 nm Nd:YAG pulsed laser operating at 10 Hz with a 10 ns pulse length and with a 300 μm spot radius.

The current-voltage characteristics were monitored for permanent change as a function of laser fluence and the degradation thresholds were found. Two types of change were observed. The first type was a large increase in bulk leakage current. It may be modeled by the introduction of defects into the depletion region by deep melting transients. The second type was catastrophic failure in which the devices were electrically shorted after irradiation. It may be modeled by excessive current density in the photodiode junction. The type of failure was determined by the parameters of the biasing circuit.