A Geiger Mode Avalanche Photodiode Fabricated in a Conventional CMOS Technology

A Geiger mode avalanche photodiode with outstanding characteristics is fully fabricated in a conventional CMOS process. The 80μm2 active area photodiode for blue detection contains an efficient guard-ring structure to prevent edge breakdown. The selectivity for blue is obtained using a P+/ Nwell/Psubstrate dual junction structure. The first junction close to the surface is biased above the breakdown voltage, the second junction is short-circuited. A characterization using a passive quenching method is done. A value of the dark count rate of only 220 c.p.s. is obtained for an excess bias voltage of -2.85V, at room temperature. The maximum Geiger mode quantum efficiency for this excess bias voltage is about 20% at λ=460nm. The fabrication in a CMOS process opens the way to the co-integration of passive quenching or active quenching depending on applications and read-out electronics.