A two-dimensional (2-D) array (4 by 8) of single-photon avalanche diodes integrated in an industrial complementary metal-oxide-semiconductor (CMOS) process is presented. Each pixel combines a photodiode biased above its breakdown voltage in the so-called Geiger mode, a quenching resistor, and a simple comparator. The pitch between the pixels is 75 mum and the diameter of each pixel is 6.4 mum. The full integration allows reducing the number of charge carriers in a Geiger pulse. The electroluminescence responsible for optical crosstalks between pixels is then reduced leading to a negligible optical crosstalk probability. Thanks to the cleanness of the fabrication process, no afterpulsing effects are noticed. At room temperature, most of the pixels exhibit a dark-count rate of about. 50 Hz. The detection probability is almost identical for all 32 pixels of the array with relative variation in the range of a-few. percents. This letter demonstrates the feasibility of an array: of single-photon detectors sensitive in the visible part of the spectrum. Besides low production costs and compactness,, an undeniable benefit lies in the potential to easily modify the design to fit a specific application. Furthermore, the CMOS integration opens the way p to on-chip data processing.
Varun Sharma, Konstantin Androsov, Xin Chen, Rakesh Chawla, Werner Lustermann, Andromachi Tsirou, Alexis Kalogeropoulos, Andrea Rizzi, Thomas Muller, David Vannerom, Albert Perez, Alessandro Caratelli, François Robert, Davide Ceresa, Yong Yang, Ajay Kumar, Ashish Sharma, Georgios Anagnostou, Kai Yi, Jing Li, Stefano Michelis, David Parker, Martin Fuchs