Single-photon avalanche diodes (SPADs) fabricated in conventional CMOS processes typically have limited near infra-red (NIR) sensitivity. This is the consequence of isolating the SPADs in a lowly-doped deep N-type well. In this work, we present a second improved version of the ācurrent-assistedā single-photon avalanche diode, fabricated in a conventional 350 nm CMOS process, having good NIR sensitivity owing to 14 Āµm thick epilayer for photon absorption. The presented device has a photon absorption area of 30 Ć 30 Āµm2, with a much smaller central active area for avalanche multiplication. The photo-electrons generated in the absorption area are guided swiftly towards the central area with a drift field created by the ācurrent-assistanceā principle. The central active avalanche area has a cylindrical p-n junction as opposed to the square geometry from the previous iteration. The presented device shows improved performance in all aspects, most notably in photon detection probability. The p-n junction capacitance is estimated to be ~1 fF and on-chip passive quenching with source followers is employed to conserve the small capacitance for bringing monitoring signals off-chip. Device physics simulations are presented along with measured dark count rate (DCR), timing jitter, after-pulsing probability (APP) and photon detection probability (PDP). The presented device has a peak PDP of 22.2% at a wavelength of 600 nm and a timing jitter of 220 ps at a wavelength of 750 nm.
Jegannathan, G, Dries, TVD & Kuijk, M 2020, 'Current-Assisted SPAD with Improved p-n Junction and Enhanced NIR Performance', Sensors, vol. 20, no. 24, 7105, pp. 1-15. https://doi.org/10.3390/s20247105
Jegannathan, G., Dries, T. V. D., & Kuijk, M. (2020). Current-Assisted SPAD with Improved p-n Junction and Enhanced NIR Performance. Sensors, 20(24), 1-15. Article 7105. https://doi.org/10.3390/s20247105
@article{5bb2a2a63a254e28aee1bd90ca64d72f,
title = "Current-Assisted SPAD with Improved p-n Junction and Enhanced NIR Performance",
abstract = "Single-photon avalanche diodes (SPADs) fabricated in conventional CMOS processes typically have limited near infra-red (NIR) sensitivity. This is the consequence of isolating the SPADs in a lowly-doped deep N-type well. In this work, we present a second improved version of the ācurrent-assistedā single-photon avalanche diode, fabricated in a conventional 350 nm CMOS process, having good NIR sensitivity owing to 14 Āµm thick epilayer for photon absorption. The presented device has a photon absorption area of 30 Ć 30 Āµm2, with a much smaller central active area for avalanche multiplication. The photo-electrons generated in the absorption area are guided swiftly towards the central area with a drift field created by the ācurrent-assistanceā principle. The central active avalanche area has a cylindrical p-n junction as opposed to the square geometry from the previous iteration. The presented device shows improved performance in all aspects, most notably in photon detection probability. The p-n junction capacitance is estimated to be ~1 fF and on-chip passive quenching with source followers is employed to conserve the small capacitance for bringing monitoring signals off-chip. Device physics simulations are presented along with measured dark count rate (DCR), timing jitter, after-pulsing probability (APP) and photon detection probability (PDP). The presented device has a peak PDP of 22.2% at a wavelength of 600 nm and a timing jitter of 220 ps at a wavelength of 750 nm.",
author = "Gobinath Jegannathan and Dries, {Thomas Van den} and Maarten Kuijk",
year = "2020",
month = dec,
day = "11",
doi = "10.3390/s20247105",
language = "English",
volume = "20",
pages = "1--15",
journal = "Sensors",
issn = "1424-8220",
publisher = "Multidisciplinary Digital Publishing Institute (MDPI)",
number = "24",
}