scholarly journals Architecture-Level Optimization on Digital Silicon Photomultipliers for Medical Imaging

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 122
Author(s):  
Franco Bandi ◽  
Victor Ilisie ◽  
Ion Vornicu ◽  
Ricardo Carmona-Galán ◽  
José M. Benlloch ◽  
...  
Keyword(s):  
Detection Efficiency ◽  
Single Photon ◽  
Spatial Location ◽  
Cmos Technology ◽  
Silicon Photomultipliers ◽  
Avalanche Diodes ◽  
Pile Up ◽  
Relevant Variables ◽  
Potential Benefits ◽  
Additional Circuitry

Silicon photomultipliers (SiPMs) are arrays of single-photon avalanche diodes (SPADs) connected in parallel. Analog silicon photomultipliers are built in custom technologies optimized for detection efficiency. Digital silicon photomultipliers are built in CMOS technology. Although CMOS SPADs are less sensitive, they can incorporate additional functionality at the sensor plane, which is required in some applications for an accurate detection in terms of energy, timestamp, and spatial location. This additional circuitry comprises active quenching and recharge circuits, pulse combining and counting logic, and a time-to-digital converter. This, together with the disconnection of defective SPADs, results in a reduction of the light-sensitive area. In addition, the pile-up of pulses, in space and in time, translates into additional efficiency losses that are inherent to digital SiPMs. The design of digital SiPMs must include some sort of optimization of the pixel architecture in order to maximize sensitivity. In this paper, we identify the most relevant variables that determine the influence of SPAD yield, fill factor loss, and spatial and temporal pile-up in the photon detection efficiency. An optimum of 8% is found for different pixel sizes. The potential benefits of molecular imaging of these optimized and small-sized pixels with independent timestamping capabilities are also analyzed.

A low dark count rate single photon avalanche diode with standard 180 nm CMOS technology

2019 ◽  
Vol 33 (09) ◽  
pp. 1950099
Author(s):  
Wei Wang ◽  
Guang Wang ◽  
Hongan Zeng ◽  
Yuanyao Zhao ◽  
U-Fat Chio ◽  
...  
Keyword(s):  
Count Rate ◽  
Detection Efficiency ◽  
Single Photon ◽  
Cmos Technology ◽  
Uniform Electric Field ◽  
Avalanche Breakdown ◽  
Guard Ring ◽  
Dark Count ◽  
Avalanche Diode ◽  
Dark Count Rate

A single photon avalanche diode (SPAD) structure designed with standard 180 nm CMOS technology is investigated in detail. The SPAD employs a [Formula: see text]-well anode, rather than the conventional [Formula: see text] layer, and with a [Formula: see text]-well/deep [Formula: see text]-well junction with square shape, a deep retrograde [Formula: see text]-well virtual guard ring which prevents the premature edge avalanche breakdown. The analytical and simulation results show that the SPAD exhibits a uniform electric field distribution in [Formula: see text]-well/deep [Formula: see text]-well junction with the active area of [Formula: see text], and the avalanche breakdown voltage is as low as 9 V, the peak of the photon detection efficiency (PDE) is about 33% at 500 nm, the relatively low dark count rate (DCR) of 0.66 KHz at room temperature is obtained.

scholarly journals Photon-Detection-Probability Simulation Method for CMOS Single-Photon Avalanche Diodes

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 436 ◽  
Author(s):  
Chin-An Hsieh ◽  
Chia-Ming Tsai ◽  
Bing-Yue Tsui ◽  
Bo-Jen Hsiao ◽  
Sheng-Di Lin
Keyword(s):  
Detection Probability ◽  
Single Photon ◽  
Cmos Technology ◽  
Oxide Semiconductor ◽  
Cmos Process ◽  
Single Photons ◽  
Photon Detection ◽  
Important Indicator ◽  
Avalanche Diodes ◽  
Single Photon Avalanche Diodes

Single-photon avalanche diodes (SPADs) in complementary metal-oxide-semiconductor (CMOS) technology have excellent timing resolution and are capable to detect single photons. The most important indicator for its sensitivity, photon-detection probability (PDP), defines the probability of a successful detection for a single incident photon. To optimize PDP is a cost- and time-consuming task due to the complicated and expensive CMOS process. In this work, we have developed a simulation procedure to predict the PDP without any fitting parameter. With the given process parameters, our method combines the process, the electrical, and the optical simulations in commercially available software and the calculation of breakdown trigger probability. The simulation results have been compared with the experimental data conducted in an 800-nm CMOS technology and obtained a good consistence at the wavelength longer than 600 nm. The possible reasons for the disagreement at the short wavelength have been discussed. Our work provides an effective way to optimize the PDP of a SPAD prior to its fabrication.

scholarly journals Single-photon avalanche diodes in 018-μm high-voltage CMOS technology

2017 ◽  
Vol 25 (12) ◽  
pp. 13333 ◽  
Author(s):  
L. D. Huang ◽  
J. Y. Wu ◽  
J. P. Wang ◽  
C. M. Tsai ◽  
Y. H. Huang ◽  
...  
Keyword(s):  
High Voltage ◽  
Single Photon ◽  
Cmos Technology ◽  
Avalanche Diodes ◽  
Single Photon Avalanche Diodes

Proton Irradiation of 4H-SiC Ultraviolet Single Photon Avalanche Diodes

2011 ◽  
Vol 679-680 ◽  
pp. 551-554
Author(s):  
D. Kurt Gaskill ◽  
Jun Hu ◽  
X. Xin ◽  
Jian Hui Zhao ◽  
Brenda L. VanMil ◽  
...  
Keyword(s):  
Proton Irradiation ◽  
Detection Efficiency ◽  
Single Photon ◽  
Photon Counting ◽  
Chemical Vapor ◽  
Single Photon Detection ◽  
Proton Radiation ◽  
Space Applications ◽  
Single Photon Counting ◽  
Avalanche Diodes

The effects of proton irradiation on uv 4H-SiC single photon avalanche photodiodes (SPADs) are reported. The SPADs, grown by chemical vapor deposition, were designed for uv operation with dark count rates (DCR) of about 30 kHz and single photon detection efficiency (SPDE) of 4.89%. The SPADs were irradiated with 2 MeV protons to a fluence of 1012 cm-2. After irradiation, the I-V characteristics show forward voltage (<1.9 V) generation-recombination currents 2 to 3 times higher than before irradiation. Single photon counting measurements imply generation-recombination centers created in the band gap after irradiation. For threshold voltage ranging from 23 to 26 mV, the 4H-SiC SPAD showed low DCR (<54 kHz) and high SPDE (>1%) after irradiation. The SPADs demonstrated proton radiation tolerance for geosynchronous space applications.

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