Optical crosstalk is one of the main factors limiting the performance of Single-Photon Avalanche Diode (SPAD) arrays and Silicon Photomultipliers (SiPMs). In this paper, a set of crosstalk measurements on a CMOS SPAD pixel array with 50 mu m x 75 mu m pitch and 51.6% Fill Factor, designed for direct particle detection, is reported. Measurements were performed on dies with different thickness: 280 mu m, 50 mu m and 25 mu m. The dependence of crosstalk on excess bias voltage and distance between pairs of pixels is presented and its overall effect on the Dark Count Rate (DCR) distribution of the array is discussed. Results show a strong dependence of crosstalk coefficient on substrate thickness, confirming the role of photon reflection on the wafer backside surface. In thinned devices, the silicon substrate acts as a planar waveguide, increasing the transmission efficiency of secondary photons and greatly enhancing long-distance optical crosstalk.
Ficorella, A., Pancheri, L., Dalla Betta, G.-., Brogi, P., Collazuol, G., Marrocchesi, P.S., et al. (2016). Crosstalk mapping in CMOS SPAD arrays. In 2016 46th European Solid-State Device Research Conference (ESSDERC) (pp.101-104). New York : IEEE [10.1109/ESSDERC.2016.7599598].
Crosstalk mapping in CMOS SPAD arrays
Brogi, P.;Marrocchesi, P. S.;
2016-01-01
Abstract
Optical crosstalk is one of the main factors limiting the performance of Single-Photon Avalanche Diode (SPAD) arrays and Silicon Photomultipliers (SiPMs). In this paper, a set of crosstalk measurements on a CMOS SPAD pixel array with 50 mu m x 75 mu m pitch and 51.6% Fill Factor, designed for direct particle detection, is reported. Measurements were performed on dies with different thickness: 280 mu m, 50 mu m and 25 mu m. The dependence of crosstalk on excess bias voltage and distance between pairs of pixels is presented and its overall effect on the Dark Count Rate (DCR) distribution of the array is discussed. Results show a strong dependence of crosstalk coefficient on substrate thickness, confirming the role of photon reflection on the wafer backside surface. In thinned devices, the silicon substrate acts as a planar waveguide, increasing the transmission efficiency of secondary photons and greatly enhancing long-distance optical crosstalk.
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https://hdl.handle.net/11365/1073288