Actively recharged single photon counting avalanche photodiode integrated in an industrial CMOS process

An actively recharged single photon counting avalanche photodiode (SPAD) is integrated in a conventional CMOS process. A fast recharge through a low impedance path leads to a dead time lower than 10 ns. This outstanding feature allows one to work with pulse repetition rate up to 100 MHz in time correlated single photon counting based experiments. Biased 2.5 V above its breakdown voltage, the 30 mum(2) sensitive area photodiode has a maximum detection probability of about 20% at lambda = 440 nm and up to 5% in the visible part of the spectrum. At this bias condition, the dark count rate is as low as 60 Hz at room temperature, making a cooling of the microsystem unnecessary. The AR-SPAD exhibits no afterpulsing phenomenon revealing the maturity of the CMOS process used. The timing resolution of the AR-SPAD is less than 50 ps. For applications where the photons can be focused on the detector with an objective, the AR-SPAD is highly competitive with commercially available single photon counter. Furthermore, CMOS integration opens the way to arrays fabrication as well as co-integration of additional functions to develop smart optical sensors. (C) 2003 Published by Elsevier B.V.