We describe the design, characterization, and demonstration of a fully integrated single-photon avalanche diode (SPAD) imager for use in time-resolved fluorescence imaging. The imager consists of a 64-by-64 array of active SPAD pixels and... more
We describe the design, characterization, and demonstration of a fully integrated single-photon avalanche diode (SPAD) imager for use in time-resolved fluorescence imaging. The imager consists of a 64-by-64 array of active SPAD pixels and an on-chip time-to-digital converter (TDC) based on a delay-locked loop (DLL) and calibrated interpolators. The imager can perform both standard time-correlated single-photon counting (TCSPC) and an
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We present a hybrid CMOS based microsystem where magnetic actuation of microparticles is combined with integrated optical detection via Single Photon Avalanche Diodes (SPADs). The system's configuration permits the manipulation and... more
We present a hybrid CMOS based microsystem where magnetic actuation of microparticles is combined with integrated optical detection via Single Photon Avalanche Diodes (SPADs). The system's configuration permits the manipulation and detection of single magnetic particles having diameters of 1, 3 and 5 µm. We are able to show a size sensitivity of the particle detection, with a clear distinction
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A solid-state imager fabricated in CMOS technology is presented for depth information capture of arbitrary 3D objects with millimeter resolution. The system is based on an array of 32x32 pixels that independently measure the... more
A solid-state imager fabricated in CMOS technology is presented for depth information capture of arbitrary 3D objects with millimeter resolution. The system is based on an array of 32x32 pixels that independently measure the time-of-flight of a ray of light as it is reflected back from the objects in a scene. A single cone of pulsed laser light illuminates the
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ABSTRACT, The design and characterization of an imaging,sensor based on single,photon avalanche,diodes is presented. The sensor was fully integrated in a 0.35µm CMOS technology. The core of the imager,is an array of 4x112 pixels that... more
ABSTRACT, The design and characterization of an imaging,sensor based on single,photon avalanche,diodes is presented. The sensor was fully integrated in a 0.35µm CMOS technology. The core of the imager,is an array of 4x112 pixels that independently,and simultaneously detect the arrival time of photons,with picosecond,accuracy. A novel event-driven readout scheme,allows parallel column-wise and non-sequential, on-demand row-wise operation. Both time-correlated and time-uncorrelated
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This paper reports on our progress in developing multibeam two-photon fluorescence lifetime imaging microscopy (FLIM) based on time-correlated single-photon counting (TCSPC). The core of the system is a 2D array of solid-state... more
This paper reports on our progress in developing multibeam two-photon fluorescence lifetime imaging microscopy (FLIM) based on time-correlated single-photon counting (TCSPC). The core of the system is a 2D array of solid-state single-photon avalanche diodes (SPADs) operating simultaneously and at room temperature. To the best of our knowledge, this is the first solid-state demonstration of a two-photon multichannel FLIM system with a time resolution of 120ps.
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ABSTRACT We present a multi-channel digital Silicon photomultipliers (MD-SiPM) capable of detecting and timestamping up to 48 photons and we show the advantage of generating multiple timestamps in the context of positron emission... more
ABSTRACT We present a multi-channel digital Silicon photomultipliers (MD-SiPM) capable of detecting and timestamping up to 48 photons and we show the advantage of generating multiple timestamps in the context of positron emission tomography (PET). The MD-SiPM has a size of 800 μm × 800 μm and comprises 416 pixels. Three versions of the pixel exists with 1, 1.5, and 2 bit counters; the effects of different counting resolutions, dead time, and afterpulsing are also discussed.
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ABSTRACT In this paper, the reverse biasing and breakdown properties of the PureB diodes are investigated for different methods of processing the PureB anode window and the metal contacting. In particular, micron-sized devices are... more
ABSTRACT In this paper, the reverse biasing and breakdown properties of the PureB diodes are investigated for different methods of processing the PureB anode window and the metal contacting. In particular, micron-sized devices are examined in order to assess their suitability for use in dense imaging arrays that may require operation as avalanche photodiodes to obtain the necessary photosensitivity [6]. For such small devices implanted guard rings cannot be implemented without paying a penalty in fill-factor. At the same time it is also desirable to position the photosensitive area away from the oxide perimeter where permanent damage can be inflicted by high reverse currents. Therefore, a “virtual” guard, using an n-enhancement implantation in the central region of the diode is applied here.
Abstract Techniques are proposed for the routing of very high-frequency circuits. In this approach, performance sensitivities are used to derive a set of bounds on critical parasitics and to generate weights for a cost function which... more
Abstract Techniques are proposed for the routing of very high-frequency circuits. In this approach, performance sensitivities are used to derive a set of bounds on critical parasitics and to generate weights for a cost function which drives an area router. In addition to these bounds, design often requires that the length of interconnect lines be equal to predefined values, The routing scheme enforces both types of constraints in two phases. During the first phase all parasitic constraints are enforced on all nets. Equality constraints are enforced ...
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Almost every aspect of today's integrated electronics at-tempts to meet tougher performance budgets, while con-tinuously shrinking device features and power constraints. An aggressive reduction of feature size often... more
Almost every aspect of today's integrated electronics at-tempts to meet tougher performance budgets, while con-tinuously shrinking device features and power constraints. An aggressive reduction of feature size often results in lower signals, which causes lower noise margins, ...
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The problem of designing complex analog circuits is attacke dusing a hier archic altop-down, constr aint-driven design methodolo gy. In this methodolo gy, constraints are prop agate dautomatically from high-level specific ationsto physic... more
The problem of designing complex analog circuits is attacke dusing a hier archic altop-down, constr aint-driven design methodolo gy. In this methodolo gy, constraints are prop agate dautomatically from high-level specific ationsto physic aldesign through a sequence of gradual transformations. Constraint tr ansformation is a critic al step in the methodolo gy, sinc e it determines in lar ge p
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An avalanche photodiode array uses single-photon counting to perform time-of-flight range-finding on a scene uniformly hit by 100ps 250mW uncollimated laser pulses. The 32×32 pixel sensor, fabricated in a 0.8 μm CMOS process uses a... more
An avalanche photodiode array uses single-photon counting to perform time-of-flight range-finding on a scene uniformly hit by 100ps 250mW uncollimated laser pulses. The 32×32 pixel sensor, fabricated in a 0.8 μm CMOS process uses a microscanner package to enhance the effective resolution in the application to 64×64 pixels. The application achieves a measurement depth resolution of 1.3mm to a depth
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In this paper we report on a 32×32 optical imager based on single photon avalanche diodes integrated in CMOS technology. The maximum measured dynamic range is 120dB and the minimum noise equivalent intensity is 1.3 × 10-3 lx. The minimum... more
In this paper we report on a 32×32 optical imager based on single photon avalanche diodes integrated in CMOS technology. The maximum measured dynamic range is 120dB and the minimum noise equivalent intensity is 1.3 × 10-3 lx. The minimum integration time per pixel is 4 μs. The output of each pixel is digital, thereby requiring no complex read-out circuitry,
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We present a single-photon avalanche diode (SPAD) with a wide spectral range fabricated in an advanced 180 nm CMOS process. The realized SPAD achieves 20 % photon detection probability (PDP) for wavelengths ranging from 440 nm to 820 nm... more
We present a single-photon avalanche diode (SPAD) with a wide spectral range fabricated in an advanced 180 nm CMOS process. The realized SPAD achieves 20 % photon detection probability (PDP) for wavelengths ranging from 440 nm to 820 nm at an excess bias of 4 V, with 30 % PDP at wavelengths from 520 nm to 720 nm. Dark count rates (DCR) are at most 5 kHz, which is 30 Hz/μm2, at an excess bias of 4V when we measure 10 μm diameter active area structure. Afterpulsing probability, timing jitter, and temperature effects on DCR are also presented.
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ABSTRACT The Ge APD detectors are fabricated on Si by using a selective chemical-vapor deposition (CVD) epitaxial growth technique. A novel processing procedure was developed for the p+ Ge surface doping by a sequence of pure-Ga and... more
ABSTRACT The Ge APD detectors are fabricated on Si by using a selective chemical-vapor deposition (CVD) epitaxial growth technique. A novel processing procedure was developed for the p+ Ge surface doping by a sequence of pure-Ga and pure-B depositions (PureGaB). Then, PVD Al is used to contact the n-type Si and the anode of p+n Ge diode. Arrays of diodes with different areas, as large as 40×40 μm2, were fabricated. The resulting p+n diodes have exceptionally good IV characteristics with ideality factor of ~1.1 and low saturation currents. The devices can be fabricated with a range of breakdown voltages from a minimum of 9 V to a maximum of 13 V. They can be operated both in proportional and in Geiger mode, and exhibit relatively low dark counts, as low as 10 kHz at 1 V excess reverse bias. The dark current at 1 V reverse bias are as low as 2 pA and 20 pA for a 2×2 μm2 and 2×20 μm2 devices, respectively. Higher IR-induced current than that induced by visible light confirms the sensitivity of Ge photodiodes at room temperature. The 25% peak in Id/Iref at an IR-wavelength of 1100 nm in Geiger mode is measured for excess bias voltages of 3 V and 4 V, where Id refers to the photocurrent of the 2×20 μm2 device at different wavelengths, and Iref is the reference photodiode current. The timing response (Jitter) for the APD when exposed to a pulsed laser at 637 nm and 1 V excess bias is measured as 900 ps at full width of half maximum (FWHM).
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A 64-by-64-pixel CMOS single-photon avalanche diode (SPAD) imager for time-resolved fluorescence detection features actively quenched and reset pixels, allowing gated detection to eliminate pile-up nonlinearities common to most... more
A 64-by-64-pixel CMOS single-photon avalanche diode (SPAD) imager for time-resolved fluorescence detection features actively quenched and reset pixels, allowing gated detection to eliminate pile-up nonlinearities common to most time-correlated single-photon counting (TCSPC) approaches. Timing information is collected using an on-chip time-to-digital converter (TDC) based on a counter and a supply-regulated delay-locked loop (DLL).
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An optical imager is reported based on single photon avalanche diodes. The imager, fabricated in 0.8μm CMOS technology, consists of an array of 1024 pixels each with an area of 58μm×58μm for a total chip area of 2.5mm×2.8mm. The... more
An optical imager is reported based on single photon avalanche diodes. The imager, fabricated in 0.8μm CMOS technology, consists of an array of 1024 pixels each with an area of 58μm×58μm for a total chip area of 2.5mm×2.8mm. The architecture of the imager is reduced to a minimum since no A/D converter is required. Moreover, since the output of each
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A three-dimensional (3-D) imager is presented, capable of computing the depth map as well as the intensity scale of a given scene. The heart of the system is a two-dimensional array of single photon avalanche diodes fabricated in standard... more
A three-dimensional (3-D) imager is presented, capable of computing the depth map as well as the intensity scale of a given scene. The heart of the system is a two-dimensional array of single photon avalanche diodes fabricated in standard CMOS technology. The diodes exhibit low-noise equivalent-power high-dynamic range, and superior linearity. The 3-D imager achieves submillimetric precision at a depth-of-field
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A new approach to the layout of integrated circuits with multiplesymmetry axes is presented in this paper. When more than one symmetryis present, the usual approach to placement and compaction makesextensive use of hierarchy, which... more
A new approach to the layout of integrated circuits with multiplesymmetry axes is presented in this paper. When more than one symmetryis present, the usual approach to placement and compaction makesextensive use of hierarchy, which requires fixed positions for symmetryaxes. As a result, wiring and area optimizations are poor.The position of a virtual symmetry axis is variable, and dynamicallydefined by
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A general methodology is presented for the generation of a complete set of constraints on interconnect parasitics, parasitic mismatch and on the physical topology of analog circuits. The parasitic and matching constraints are derived from... more
A general methodology is presented for the generation of a complete set of constraints on interconnect parasitics, parasitic mismatch and on the physical topology of analog circuits. The parasitic and matching constraints are derived from high-level performance specifications by means of sensitivity analysis in time and frequency domain using quadratic optimization. Topological constraints are obtained by using sensitivity and matching
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... Cristiano Niclass, Student Member, IEEE, Alexis Rochas, Pierre-André Besse, and Edoardo Charbon, Member, IEEE ... for this behavior is that the peak electric field is located only in the diode's periphery, thus causing... more
... Cristiano Niclass, Student Member, IEEE, Alexis Rochas, Pierre-André Besse, and Edoardo Charbon, Member, IEEE ... for this behavior is that the peak electric field is located only in the diode's periphery, thus causing premature breakdown [8]. Biased just below , an avalanche ...
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New design paradigms based on the concept of system-on-chip are gradually replacing printed circuit board centric approaches. This trend is mainly due to two factors: far higher running speeds and greater miniaturization. The new... more
New design paradigms based on the concept of system-on-chip are gradually replacing printed circuit board centric approaches. This trend is mainly due to two factors: far higher running speeds and greater miniaturization. The new paradigms will accelerate design cycles, which in turn will force designers to reuse existing and acquire new circuits ready to be integrated. Such acceleration will be
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Poisson distributed spike trains are often used as the input to VLSI implementations of spiking neural networks. However, it can be difficult to generate large truly random spike distributions which can be easily applied as input to a... more
Poisson distributed spike trains are often used as the input to VLSI implementations of spiking neural networks. However, it can be difficult to generate large truly random spike distributions which can be easily applied as input to a chip. This work presents results recorded from an avalanche photo diode which demonstrates that it can be used to create a Poisson
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ABSTRACT
ABSTRACT Planetary surface exploration using laser induced breakdown spectroscopy (LIBS) to probe the composition of rocks has recently become a reality with the operation of the mast-mounted ChemCam instrument onboard the Curiosity... more
ABSTRACT Planetary surface exploration using laser induced breakdown spectroscopy (LIBS) to probe the composition of rocks has recently become a reality with the operation of the mast-mounted ChemCam instrument onboard the Curiosity rover. Following this success, Raman spectroscopy has steadily gained support as a means for using laser spectroscopy to identify not just composition but mineral phases, without the need for sample preparation. The RLS Raman Spectrometer is included on the payload for the ExoMars mission, and a Raman spectrometer has been included in an example strawman payload for NASA’s Mars 2020 mission. Raman spectroscopy has been identified by the community as a feasible means for pre-selection of samples on Mars for subsequent return to Earth. We present a next-generation instrument that builds on the widely used green-Raman technique to provide a means for performing Raman spectroscopy without the background noise that is often generated by fluorescence of minerals and organics. Microscopic Raman spectroscopy with a laser spot size smaller than the grains of interest can provide surface mapping of mineralogy while preserving morphology. A very small laser spot size 1 µm) is often necessary to identify minor phases that are often of greater interest than the matrix phases. In addition to the difficulties that can be posed by fine-grained material, fluorescence interference from the very same material is often problematic. This is particularly true for many of the minerals of interest that form in environments of aqueous alteration and can be highly fluorescent. We use time-resolved laser spectroscopy to eliminate fluorescence interference that can often make it difficult or impossible to obtain Raman spectra. We will discuss significant advances leading to the feasibility of a compact time-resolved spectrometer, including the development of a new solid-state detector capable of sub-ns time resolution. We will present results on planetary analog minerals to demonstrate the instrument performance including fluorescence rejection.