8 research outputs found
Progress in Quenching Circuits for Single Photon Avalanche Diodes
No full textAbstract—An ever wider variety of applications employ Single
Photon Avalanche Diodes (SPADs) for the detection of faint optical
signals. SPADs are p-n junction biased above the breakdown
voltage and operate in Geiger-mode: each electron-hole pair can
trigger an avalanche multiplication process that causes the current
to swiftly rise to its final value. Additional quenching electronics
is necessary for a SPAD proper working. The additional
electronics characteristics directly affect the system’s obtainable
performances. Different quenching circuits affect the detector performances
in different ways. In the last 15 years there has been
considerable development in the integration of the quenching circuitry
directly with the detector, thus leading to improved performances.
This paper reviews the state of the art of this evolution,
examining and comparing different classes of quenching circuits
and explaining their mode of operations, their advantages and disadvantages
Complete single photon counting and timing module in a microchip
No full textA 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-μm-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
Monolithic CMOS Detector Module for Photon Counting and Picosecond Timing
No full textA monolithic optoelectronic module for counting and timing single optical photons has been designed and fabricated in CMOS technology. It integrates a single-photon avalanche diode (SPAD) of 12 μm-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 20 V. The on-chip electronics detects the rise of the current triggered by a photogenerated carrier, then swiftly quenches the avalanche by controlling the SPAD bias voltage, and finally resets the detector after a hold-off time (adjustable from 0 to 350 ns). In a chip of 700 μm×1,000 μm, the overall performance is comparable or better than that of macroscopic modules available from leading industries
Parallel fluorescence photon timing module with monolithic SPAD array detector
No full textOver the past few years there has been a growing interest in monolithic arrays of single photon avalanche diodes (SPAD) for time resolved detection of faint ultrafast optical signals. SPADs implemented in CMOS-compatible planar technologies offer the typical advantages of microelectronic devices (small size, ruggedness, low voltage, low power, etc.). Furthermore, they have inherently higher photon detection efficiency than PMTs and are able to provide, beside sensitivities down to single-photons, very high acquisition speeds. They are in principle therefore ideal candidates for the development of new parallel systems analysis. The birth of novel techniques and diagnostic instruments in fact has led towards the parallelization of measurement systems and consequently to the development of monolithic arrays of detectors. Unfortunately, the implementation of a multidimensional system is a challenging task, because optical and electrical crosstalk between adjacent channels strongly affect the timing performances of the SPADs; for these reasons, only a few number of commercial solutions are available and their performances are not comparable to the best single channel ones. A new compact module based on a 8x1 high performance time resolved SPAD array with a new timing approach is here presented
Avalanche buildup and propagation effects on photon-timing jitter in Si-SPAD with non-uniform electric field
No full textImproving 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
Monolithic active quenching and picosecond timing circuit suitable for large-area single-photon avalanche diodes
No full textA 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 activequenching 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
