Photon counting in one or in arrays of pixels is useful in a number of applications, from more traditional ones, such as low-light-level and fluorescence imaging, superresolution microscopy, 3D time-of-flight sensing, and NIR optical tomography [1-6], to niche applications, such as voltage-sensitive-dye (VSD)-based imaging [7,8], particle image velocimetry [9], instantaneous gas imaging [10,11], fluorescence-based time-resolved imaging (both single- and multiphoton, and lifetime, and correlation based) [12-14], and applications based on time domain interferometry, like the Hanbury Brown-Twiss interferometry, for the analysis of microlight and macrolight sources as well as for stellar bodies [15-17]. In this context, and in the context of consumer applications, compactness, weight, and power consumption have prompted a boost to the development of solid-state photon-counting sensors, where 186photoelectrons are multiplied in single-sided abrupt junctions operating at high electric fields that can sustain impact ionization. These structures are generally based on a technology that is known as Geiger-mode avalanche photodiode or single-photon avalanche diode (SPAD), whereas the first devices of this kind were vertically integrated in dedicated processes, e.g., reach-through avalanche photodiode (RAPD) based on p+-π-p-n [18].@en

In this paper, a novel CMOS single-photon avalanche diode (SPAD) is presented, and the device is designed using a vertical p-i-n diode construction. The p-i-n diode with a wide depletion region enables a low-noise operation. The proposed design achieves dark count rates of 1.5 cps/μm2 at 11 V excess bias, while the photon detection probability (PDP) is greater than 40% from 460 to 600 nm. Through the operation at very high excess bias voltages, it is possible to reach the PDP compression point where sensitivity to the breakdown voltage is low, thus ensuring high PDP uniformity; this feature makes it, especially, suitable for multimegapixel SPAD arrays.@en

geen tijdschrift/proceedings bekend.@en