Total dose test with gamma-ray for silicon single photon avalanche diodes

Gamma-ray radiation for silicon single photon avalanche diodes (Si SPADs) is evaluated, with total dose of 100 krad(Si) and dose rate of 50 rad(Si)/s by using 60Co as gamma-ray radiation source. The breakdown voltage, photocurrent and gain have no obvious change after radiation. However, both the leakage current and dark count rate increase by about one order of magnitude above the values before radiation. Temperature-dependent current-voltage measurement results indicate the traps caused by radiation function as generation and recombination centers. Both leakage current and dark count rate can be almost recovered after annealing at 200℃ for about 2 hours, which verified the radiation damage mechanics.