Large-area CMOS SPADs with very low dark counting rate

Abstract

We designed and characterized Silicon Single-Photon Avalanche Diodes (SPADs) fabricated in a high-voltage 0.35 μm CMOS technology, achieving state-of-the-art low Dark Counting Rate (DCR), very large diameter, and extended Photon Detection Efficiency (PDE) in the Near Ultraviolet. So far, different groups fabricated CMOS SPADs in scaled technologies, but with many drawbacks in active area dimensions (just a few micrometers), excess bias (just few Volts), DCR (many hundreds of counts per second, cps, for small 10 μm devices) and PDE (just few tens % in the visible range). The novel CMOS SPAD structures with 50 μm, 100 μm, 200 μm and 500 μm diameters can be operated at room temperature and show DCR of 100 cps, 2 kcps, 20 kcps and 100 kcps, respectively, even when operated at 6 V excess bias. Thanks to the excellent performances, these large CMOS SPADs are exploitable in monolithic SPAD-based arrays with on-chip CMOS electronics, e.g. for time-resolved spectrometers with no need of microlenses (thanks to high fillfactor). Instead the smaller CMOS SPADs, e.g. the 10 μm devices with just 3 cps at room temperature and 6 V excess bias, are the viable candidates for dense 2D CMOS SPAD imagers and 3D Time-of-Flight ranging chips

Planar CMOS analog SiPMs: design, modeling, and characterization

“…Custom technologies are exploited in order to optimize the performance of SiPMs, in terms of dark count rate (DCR) and PDE, however, it doesn't allow the integration of complex electronics. High-performance SPADs in 0.35 μm CMOS technology have already been demonstrated in [18] [19]. We designed for the first time analog SiPM in standard 0.35 μm CMOS technology.…”

Front-End Electronics for Silicon Photomultipliers

“…Further, the device's noise performance, compared with the state of the art in Figure 8.11, shows that the noise performance attained in this work is better than most of the CMOS SPADs, and it is comparable with the devices that are presented Excess bias (V) Dark count rate per micrometer square Webster 130 nm [82] Bronzi 350 nm [93] Leitner 180 nm [92] Wu 250 nm [94] Richardson 130 nm [30] Niclass 350 nm [3] Mandai 180 nm [83] Niclass 130 nm [79] Gersbach 130 nm [78] is work 180 nm in [94] and [82]. A comprehensive performance analysis of published SPADs is freely available in http://aqua.epfl.ch/spads.…”

“…In addition, while a large memory is beneficial in increasing the counting resolution, and thus the dynamic range for a given readout speed, it further absorbs area and power, thus further increasing the pitch and decreasing the size of a feasible array. Although Richardson [30] improved the DCR by design using a p-well/DNW junction, the device spectral response remained identical to conventional designs [78,79,92,93]. Both techniques have been shown successfully in [76] and [39,63], respectively.…”

Advances in time-of-flight and time-correlated single-photon-counting devices

“…As shown in Figure 2, the noise rises to just 100cps for 50 m active area diameter SPADs, and remains below 100,000cps for those devices with 500 m active area diameters under the same operating conditions. 3 The SPADs we have developed yield high photon-detection efficiencies in a wide wavelength range, between 250nm (UV) and 1000nm (near-IR). This strong absorption is due to the modified stoichiometry of the silicon nitride-based passivation layer that is commonly used in CMOS processes.…”