A Back Illuminated 6 µm SPAD Pixel Array with High PDE and Timing Jitter Performance

Shimada, Sohei; Otake, Yusuke; Yoshida, S.; Endo, S.; Nakamura, R.; Tsugawa, H.; Ogita, T.; Ogasahara, Takayuki; Yokochi, Keiichi; Inoue, Y.; Takabayashi, Kazumasa; Maeda, H.; Yamamoto, K.; Ono, M.; Matsumoto, S.; Hiyama, Hirokuni; Wakano, T.

doi:10.1109/iedm19574.2021.9720639

Cited by 20 publications

(18 citation statements)

References 4 publications

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“…Generally speaking, developing larger arrays allows a parallelization of the acquisition, reducing the measurement time. However, SPAD arrays still present relatively large pixel pitch (down to 6 μm in the best case [74]) and higher power consumption with respect to conventional image sensors. On the other hand, operating in Geiger mode, they provide single photosensitivity.…”

Section: Discussionmentioning

confidence: 99%

“…Sony published in Kumagai [72] a 189 × 600 SPAD array in 90 nm SPAD/40 nm logic, developed for LiDAR, demonstrating remarkably high detection efficiency in the NIR (22% at 905 nm) and making use of SPAD clusters for coincidence detection and built-in Digital Signal Processing (DSP) blocks to process the timing information, allowing successful ranging beyond 150 m. A second sensor presented by the same company in Ogi [73] targets lowlight imaging, exploiting the same technology to implement high frame rate color imaging over a large dynamic range, by dynamically combining SPC at low light levels with measuring the time required for overflowing the same counter at higher photon fluxes. The company, in Shimada [74], presented its new generation of stacked SPAD arrays, manufacturing the readout chip in 22 nm CMOS, reducing SPAD pitch to 6 μm and increasing detection efficiency beyond 30% at 905 nm.…”

Section: D-stacked Complementary Metal-oxide Semiconductor Single-pho...mentioning

confidence: 99%

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Historical Perspectives, State of Art and Research Trends of SPAD Arrays and Their Applications (Part II: SPAD Arrays)

et al. 2022

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The ability to detect single photons is becoming an enabling key capability in an increasing number of fields. Indeed, its scope is not limited to applications that specifically rely on single photons, such as quantum imaging, but extends to applications where a low signal is overwhelmed by background light, such as laser ranging, or in which faint excitation light is required not to damage the sample or harm the patient. In the last decades, SPADs gained popularity with respect to other single-photon detectors thanks to their small size, possibility to be integrated in complementary metal-oxide semiconductor processes, room temperature operability, low power supply and, above all, the possibility to be fast gated (to time filter the incoming signal) and to precisely timestamp the detected photons. The development of large digital arrays that integrates the detectors and circuits has allowed the implementation of complex functionality on-chip, tailoring the detectors to suit the need of specific applications. This review proposes a complete overview of silicon SPADs characteristics and applications. In the previous Part I, starting with the working principle, simulation models and required frontend, the paper moves to the most common parameters adopted in literature for characterizing SPAD performance and describes single pixels applications and their performance. In this Part II, the focus is posed on the development of SPAD arrays, presenting some of the most notable examples found in literature. The actual exploitation of these designs in real applications (e.g., automotive, bioimaging and radiation detectors) is then discussed.

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Section: Discussionmentioning

confidence: 99%

Section: D-stacked Complementary Metal-oxide Semiconductor Single-pho...mentioning

confidence: 99%

Historical Perspectives, State of Art and Research Trends of SPAD Arrays and Their Applications (Part II: SPAD Arrays)

et al. 2022

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“…For example, we previously achieved a 2× increase in fill factor by integrating a custom microlens array onto the chip, [14] while other SPADs have used a combination of microlenses and 3D stacking to optimize the fill factor. [19] Recently developed SPADs [20] featuring multibit pixels and efficiency > 50% will likely lead to further substantial additional improvements in signal to noise ratios, with greater proportions of detected photons reducing the When the optical trace of cell #1 was compared with the ground-truth electrical trace, the correctly detected spikes were marked with a red dot, the false negative spikes were marked with a grey dot, the false positive spikes were marked with a grey cross. E,F) Peristimulus time histogram (PSTH) of spiking activity between Cell #1 and Cell #2 from (B).…”

Section: Discussionmentioning

confidence: 99%

“…For example, we previously achieved a 2× increase in fill factor by integrating a custom microlens array onto the chip, [ 14 ] while other SPADs have used a combination of microlenses and 3D stacking to optimize the fill factor. [ 19 ] Recently developed SPADs [ 20 ] featuring multibit pixels and efficiency > 50% will likely lead to further substantial additional improvements in signal to noise ratios, with greater proportions of detected photons reducing the shot noise. For example, while the SPAD we used here was designed for acquisition of binary frames to allow for compact pixels built into a relatively large array, introduction of multi‐bit photon counting will increase the dynamic range of the sensor, potentially enabling lower magnification objectives to be used, and more neurons to be captured in the field of view.…”

Section: Discussionmentioning

confidence: 99%

Single Photon Kilohertz Frame Rate Imaging of Neural Activity

et al. 2022

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Establishing the biological basis of cognition and its disorders will require high precision spatiotemporal measurements of neural activity. Recently developed genetically encoded voltage indicators (GEVIs) report both spiking and subthreshold activity of identified neurons. However, maximally capitalizing on the potential of GEVIs will require imaging at millisecond time scales, which remains challenging with standard camera systems. Here, application of single photon avalanche diode (SPAD) sensors is reported to image neural activity at kilohertz frame rates. SPADs are electronic devices that when activated by a single photon cause an avalanche of electrons and a large electric current. An array of SPAD sensors is used to image individual neurons expressing the GEVI Voltron-JF525-HTL. It is shown that subthreshold and spiking activity can be resolved with shot noise limited signals at frame rates of up to 10 kHz. SPAD imaging is able to reveal millisecond scale synchronization of neural activity in an ex vivo seizure model. SPAD sensors may have widespread applications for investigation of millisecond timescale neural dynamics.

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“…Recent advances in SPAD detector design have shrunk the SPAD pitch down to 6 µm [3] and the first 2D SPAD arrays at a similar pitch were reported in [2] and [3]. However, both pixel designs remain single-bin and leave the time-of-flight signal integration outside the pixel matrix.…”

Section: Introductionmentioning

confidence: 99%

An Indirect Time-of-Flight SPAD Pixel With Dynamic Comparator Reuse for a Single-Slope ADC

Buckbee,

Dutton,

Henderson

2022

IEEE Solid-State Circuits Lett.

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This paper presents a 2-bin SPAD-based indirect time-of-flight (ITOF) pixel circuit with low power low-voltage differential clock distribution and a partially in-pixel single-slope ADC. An in-pixel dynamic comparator performs dual functions as a SPAD event-driven low-swing clock sampler and a comparator for self-referenced ADC conversion with digital delta reset sampling (DRS). The pixel achieves a full well capacity of 128 -512 photons (6.83 -8.82 ENOB), a low dynamic power consumption of 13.9-24.5 nW/MHz SPAD rate at a pitch of 7.2 µm in STMicroelectronics' 40nm CMOS and is 3D stacking ready.

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A Back Illuminated 6 µm SPAD Pixel Array with High PDE and Timing Jitter Performance

Cited by 20 publications

References 4 publications

Historical Perspectives, State of Art and Research Trends of SPAD Arrays and Their Applications (Part II: SPAD Arrays)

Historical Perspectives, State of Art and Research Trends of SPAD Arrays and Their Applications (Part II: SPAD Arrays)

Single Photon Kilohertz Frame Rate Imaging of Neural Activity

An Indirect Time-of-Flight SPAD Pixel With Dynamic Comparator Reuse for a Single-Slope ADC

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