Abstract—An ever wider variety of applications employ Single\ud Photon Avalanche Diodes (SPADs) for the detection of faint optical\ud signals. SPADs are p-n junction biased above the breakdown\ud voltage and operate in Geiger-mode: each electron-hole pair can\ud trigger an avalanche multiplication process that causes the current\ud to swiftly rise to its final value. Additional quenching electronics\ud is necessary for a SPAD proper working. The additional\ud electronics characteristics directly affect the system’s obtainable\ud performances. Different quenching circuits affect the detector performances\ud in different ways. In the last 15 years there has been\ud considerable development in the integration of the quenching circuitry\ud directly with the detector, thus leading to improved performances.\ud This paper reviews the state of the art of this evolution,\ud examining and comparing different classes of quenching circuits\ud and explaining their mode of operations, their advantages and disadvantages

Improving SPAD performances, such as dark count rate and quantum efficiency, without degrading the photontiming jitter is a challenging task that requires a clear understanding of the physical mechanisms involved. In this paper we investigate the contribution of the avalanche buildup statistics and the lateral avalanche propagation to the photon-timing jitter in silicon SPAD devices. Recent works on the buildup statistics focused on the uniform electric field case, however these results can not be applied to Si SPAD devices in which field profile is far from constant. We developed a 1-D Monte Carlo (MC) simulator using the real non-uniform field profiles derived from Secondary Ion Mass Spectroscopy (SIMS) measurements. Local and non-local models for impact ionization phenomena were considered. The obtained results, in particular the mean multiplication rate and jitter of the buildup filament, allowed us to simulate the statistical spread of the avalanche current on the device active area. We included space charge effects and a detailed lumped model for the external electronics and parasitics. We found that, in agreement with some experimental evidences, the avalanche buildup contribution to the total timing jitter is non-negligible in our devices. Moreover the lateral propagation gives an additional contribution that can explain the increasing trend of the photon-timing jitter with the comparator threshold

A new integrated active quenching circuit (i-AQC) designed in a standard CMOS process is presented, capable of operating with any available single photon avalanche diode (SPAD) over wide temperature range. The circuit is suitable for attaining high photon timing resolution also with wide-area SPADs. The new i-AQC integrates the basic active-quenching loop, a patented low-side timing circuit comprising a fast pulse pick-up scheme that substantially improves time-jitter performance, and a novel active-load passive quenching mechanism (consisting of a current mirror rather than a traditional high-value resistor) greatly improves the maximum counting rate. The circuit is also suitable for portable instruments, miniaturized detector modules and SPAD-array detectors. The overall features of the circuit may open the way to new developments in diversified applications of time-correlated photon counting in life sciences and material sciences.

A complete module for single-photon counting and timing is demonstrated in a single chip. Features comparable with or better than commercially available macroscopic modules are obtained by integration of an active-quenching and active-reset circuit in complementary metal-oxide semiconductor technology together with a single-photon avalanche diode (SPAD). The integrated SPAD has a 12-microm-diameter sensitive area and operates with an overvoltage above breakdown adjustable up to 20 V. With a 5-V overvoltage the photon detection efficiency peaks above 40% around 500 nm, and the dark-counting rate is lower than 600 counts/s at room temperature. The overall counting dead time is 33 ns.

A monolithic optoelectronic module.for counting and timing single optical photons has been designed and fabricated in CMOS technology It integrates a SinglePhoton Avalanche Diode (SPAD) ofl2pm-diameter with a complete active-quenching and active-reset circuit. The detector operates in Geiger-mode biased above breakdown level, with overvoltage adjustable up to 20V. The on-chip electronics detects the rise of the current triggered by a photogenerated carrier, then swftly quenches the avalanche by controlling the SPAD bias voltage. and finally resets the detector after a hold-off time (adjustablefrom 0 to 350ns). Thefast sensing stage limits the avalanche charge and hence the afterpulsing probability, which is further reduced below 0.02% by exploiting the hold-off fzature. Good photon detection efficiency (above 20% over all the range from 400nm to 700nm. with 40% peak at 500nm) is obtained together with low intrinsic detector noise (dark counting rate lower than 600cps at 5V excess bias voltage). In a chip of 700pm x 1.000pm, the overall performance is comparable or better than that of macroscopic modules available from leading industries. Single Photon Detectors and CircuitsPhoton-counting modules are required in many industrial and scientific applications like: time-of-flight, quantum cryptography, particle sizing, fluorescence spectrometry, single molecule detection, etc. The basic requirements are adequate active area (at least a few tens of micron diameter), low noise (below Ikcps), small time jitter (few tens of ps), good detection efficiency in the visible and near-infrared range.Photomultiplier tubes can detect ultraweak and ultrafast optical signals, hut they are bulky, delicate and sensitive to magnetic fields, require high voltage supply and signal conditioning. Ordinary avalanche photodiodes (APD) offer the advantage of solid-state devices, hut they have limited gain and high excess noise. Singlephoton avalanche diodes (SPAD) [l] attain the ultimate sensitivity and detect single photons by exploiting the positive feedback in avalanche multiplication above the breakdown level. SPAD devices have been fabricated in different technologies: reach-through dedicated 121 131, planar 141 and CMOS-like 151 [6]. 341The self-sustaining avalanche process must he quenched and the SPAD must then he reset to quiescent level. Simple passive quenching [7] is obtained with a high-value ballast resistance, hut it is the ActiveQuenching Circuit (AQC) concept [ l ] that made possible to exploit at hest the SPAD performance [7]. Various discrete-component AQCs have heen reported [I] [2], 181, 191; attempts to integrate detector and electronics have also been reported. Ref.[10] presents a circuit with passive quenching and active reset, integrated with a SPAD of 3pm-diameter operating with only 2.5V overvoltage. Ref. 151 reports arrays of SPADs with 3V overvoltage, integrated with digital CMOS circuitry for measuring photon arrival times with 700ps timing resolution.In these cases, the current onset was sensed by means of simp...