Pseudo-planar Ge-on-Si Single-photon Avalanche Diode Detector with Record Low Noise-equivalent Power

Millar, R. W. et al. (2021) Pseudo-planar Ge-on-Si Single-photon Avalanche Diode Detector with Record Low Noise-equivalent Power. In: SPIE PHOTONEX, Glasgow, UK, 28 Sep - 01 Oct 2021, (doi: 10.1117/12.2599033)

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Single-photon avalanche diode (SPAD) detectors are of significant interest for numerous applications, including light detection and ranging (LIDAR), and quantum technologies such as quantum-key distribution and quantum information processing. Here we present a record low noise-equivalent-power (NEP) for Ge-on-Si SPADs using a pseudo-planar design, showing high detection efficiency in the short-wave infrared; a spectral region which is key for quantum technologies and hugely beneficial for LIDAR. These devices can leverage the benefits of Si avalanche layers, with lower afterpulsing compared to InGaAs/InP, and reduced cost due to Si foundry compatibility. By scaling the SPAD pixels down to 26μm diameter, a step change in performance has been demonstrated, with significantly reduced dark count rates (DCRs), and low jitter (134ps). Ge-on-Si SPADs were fabricated using photolithography techniques and characterised using time-correlated single-photon counting. The DCR reaches as low as kilocount/s at 100K for excess bias up to ~5%. This reduction in DCR enables higher temperature operation; e.g. the DCR of a 26μm diameter pixel at 150 K is approximately equivalent to a 100 μm diameter pixel at 77 K (100s of kilocounts/s). These low values of DCR, coupled with the relatively temperature independent single photon detection efficiencies (SPDE) of ~29% (at 1310nm wavelength) leads to a record low NEP of 7.7×10−17WHz−1/2. This is approximately 2 orders of magnitude lower than previous similarly sized mesa-geometry Ge-on-Si SPADs. This technology can potentially offer a lowcost, Si foundry compatible SPAD operating at short-wave infrared wavelengths, with potential applications in quantum technologies and autonomous vehicle LIDAR.

Item Type:Conference Proceedings
Glasgow Author(s) Enlighten ID:Millar, Dr Ross and Watson, Dr Scott and Coughlan, Mr Conor and Benakaprasad, Miss Bhavana and Paul, Professor Douglas and Kirdoda, Mr Jaroslaw
Authors: Millar, R. W., Kirdoda, J., Thorburn, F., Yi, X., Greener, Z. M., Huddleston, L., Benakaprasad, B., Watson, S., Coughlan, C., Buller, G. S., and Paul, D. J.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Copyright Holders:Copyright © 2021 SPIE
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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