Memory effect in silicon time-gated single-photon avalanche diodes

Abstract

Articles you may be interested inWe present a comprehensive characterization of the memory effect arising in thin-junction silicon Single-Photon Avalanche Diodes (SPADs) when exposed to strong illumination. This partially unknown afterpulsing-like noise represents the main limiting factor when time-gated acquisitions are exploited to increase the measurement dynamic range of very fast (picosecond scale) and faint (single-photon) optical signals following a strong stray one. We report the dependences of this unwelcome signal-related noise on photon wavelength, detector temperature, and biasing conditions. Our results suggest that this so-called "memory effect" is generated in the deep regions of the detector, well below the depleted region, and its contribution on detector response is visible only when time-gated SPADs are exploited to reject a strong burst of photons. V C 2015 AIP Publishing LLC.[http://dx

A Versatile Setup for Time-Resolved Functional Near Infrared Spectroscopy Based on Fast-Gated Single-Photon Avalanche Diode and on Four-Wave Mixing Laser

“…This effect is as high as the source-detector distance decreases, since the peak of early photons increases. On the other side, the memory effect [27] causes a boost in the background level at longer delays that can hide the late photons, thus decreasing the maximum contrast achievable. Since the memory effect is proportional to the number of photons impinging on the detector when it is in the OFF state, its consequences are more evident when using a small source-detector distance.…”

Time-Gated Single-Photon Detection in Time-Domain Diffuse Optics: A Review

“…The possibility to operate a SPAD in TG regime, by extending the dynamic range, highlights a previously unknown source of background noise affecting these devices, which was hidden orders of magnitude below their response peak [111,112]. This phenomenon was named as "memory effect" as it arises in SPADs when exposed to strong illumination before being turned ON, giving a sort of memory of photons impinging on the active area before the gate-ON window [110].…”

“…The contribution of the memory effect to the IRF is similar to an additional diffusion tail. Probably, it is due to charge carriers generated in the deepest layers of the SPAD, well beyond the neutral region giving the classical response tail described in Section 3.7.2 [112]. This hypothesis is in agreement with the amplitude of this decay (attaching different orders of magnitude below the SPAD response peak due to the low probability that such carriers have to succeed in reaching the depleted region to generate an avalanche) and with its time constant (in the range of hundreds of ns due to the long diffusion time needed to reach the depleted region).…”

“…It is evident that the use of TG technique is fundamental when ρ = 5 mm is used to see a deep inclusion. However, due to the memory effect [111,112], the theoretical gain in depth sensitivity is not attained when using a very small ρ. Indeed, using ρ = 15 mm with the TG technique it is possible to detect the inclusion up to a depth of 31 mm with a good localization and an improvement of around 50% with respect to the non-gated acquisitions.…”

Characterization of a time-resolved non-contact scanning diffuse optical imaging system exploiting fast-gated single-photon avalanche diode detection

“…Its value was obtained in an initial measurement without clipping the curve by the gate. An additional background component due to the "memory effect" 26,31 is related to the total amount of light impinging on the detector when it is off and thus increases with increasing delay. Therefore it cannot be subtracted as a constant background but should remain part…”