Silicon photomultipliers with area up to 9 mm2 in a 0.35 mm CMOS process

Silicon photomultipliers produced using standard complementary metal oxide semiconductor (CMOS) processes are at the basis of modern applications of sensors for weak photon fluxes. They allow in fact integrating transistor-based electronic components within sensors and providing intelligent read-out strategies. In this paper we investigate the scalability of a 0.35 mm CMOS process to large area devices. We report the design and characterization of SiPMs with a total area of 1 mm², 4 mm² and 9 mm². Cross talk, photon detection efficiency at 420 nm, gain at 2.5 V overvoltage and breakdown voltage temperature coefficient do not depend on the total area of the sensor and are 10%, 35%, 2.5x106 and 35 mV/K respectively. The dark count rate scales with the total area of the device as 180 kHz/mm². The total output capacitance, the decay time of the single photon signal and the single photon time resolution depend on the area of the device. We obtain a capacitance of 66.9 pF, 270.2 pF and 554.0 pF, a decay time of (27.1 ± 0.1) ns, (50.8 ± 0.1) ns and (78.2 ± 0.1) ns and a single photon time resolution of (77.97 ± 0.51) ps, (201.67 ± 0.98) ps and (282.28 ± 0.86) ps for the 1 mm² , 4 mm² and 9 mm² SiPMs respectively.