First passively-quenched single photon counting avalanche photodiode element integrated in a conventional CMOS process with 32ns dead time

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A passively quenched single photon counting avalanche diode (PQ-SPAD) is integrated in a conventional CMOS process. Co-integration of passive quenching circuit and photodiode leads to a robust pulse and a dead time as low as 32ns. The FWHM timing resolution of the PQ-SPAD is 50ps. The 30mm2 photosensitive area photodiode has a maximum photon detection probability about 20% at λ=460nm, 5% at λ=700nm and 1% at λ=900nm. The dark count rate is 300Hz at room temperature and follows a poissonian distribution. By a cooling of the detector at -20°C, a dark count rate in the 10Hz range can be obtained. The afterpulsing probability is 2.5% at room temperature with 80% of the afterpulses located in the first 100ns after the avalanche event. The PQ-SPAD is well suited for detection applications in the visible and near infrared wavelengths and where the light can be concentrated on the active area using a high magnification objective. The PQ-SPAD also offers gated operation possibility for applications where the arrival of the photons is known. Due to its outstanding characteristics obtained at very low cost, the PQ-SPAD element opens the way to integration of detector arrays.