A new single-photon avalanche diode in 90nm standard CMOS technology

We report on the first implementation of a single-photon avalanche diode (SPAD) in 90nm complementary metal oxide semiconductor (CMOS) technology.The detector features an octagonal multiplication region and a guard ring to prevent premature edge breakdown using a standard mask set exclusively.The proposed structure emerged from a systematic study aimed at miniaturization, while optimizing overall performance.The guard ring design is the result of an extensive modeling effort aimed at constraining the multiplication region within a well-defined area where the electric field exceeds the critical value for impact ionization.The device exhibits a dark count rate of 8.1 kHz, a maximum photon detection probability of 9% and the jitter of 398ps at a wavelength of 637nm, all of them measured at room temperature and 0.13V of excess bias voltage.An afterpulsing probability of 32% is achieved at the nominal dead time.Applications include time-of-flight 3D vision, fluorescence lifetime imaging microscopy, fluorescence correlation spectroscopy, and time-resolved gamma/X-ray imaging.Standard characterization of the SPAD was performed in different bias voltages and temperatures.