Single photon detector fabricated in a complementary metal–oxide–semiconductor high-voltage technology

In this article, a fully integrated single photon detector including a silicon avalanche photodiode and a quenching circuit is presented. The low doping concentrations, inherent to the complementary metal–oxide–semiconductor (CMOS) high-voltage technology used, favor the absorption of red and infrared photons at the depletion region. The detection probability rapidly increases with excess bias voltages up to 5 V. At this value, the detection probability is larger than 20% between 420 nm and 620 nm and still 7% at 750 nm. The photosensitive area is 7 μm in diameter. Cointegration of the diode and the quenching resistor allows a drastic reduction of parasitic capacitances. Though passively quenched, the single photon detector exhibits a dead time as low as 75 ns. The avalanche current is quickly quenched in less than 3.5 ns leading to a relatively low afterpulsing probability of 7.5% at 5 V excess bias voltage. The afterpulses are located in the first microseconds after the avalanche event. At room temperature, the dark count rate is about 900 Hz at 5 V excess bias voltage. Cooling of the sensor below 0 °C is of minor interest since the tunneling process becomes dominant. A remarkably short timing resolution has been obtained with values lower than 50 ps for excess bias voltage higher than 5 V. The industrial CMOS high-voltage technology used guarantees low production costs. In applications where the light can be focused on the small photosensitive area using a high magnification objective, the fabricated single photon avalanche photodiode overcomes the features of standard photomultiplier tubes. The CMOS integration opens the way to the fabrication of an extremely compact array. The design can be easily fitted to a dedicated application. Furthermore, by using an industrial CMOS process, the cointegration of data processing electronics to produce a smart sensor would be a feasible task.