Journal Article

Recent Advancements in HgCdTe APDs for Space Applications

McCurdy, James, Sun, Xiaoli, Schaake, Christopher, Beck, Jeffrey D, Anderson, P. Duke, Mitra, Pradip, Sullivan, William, Skokan, Mark

2022

Overview

This work reports on recent advancements in the development of the Hg1−xCdxTe linear-mode, electron-initiated avalanche photodiode at Leonardo DRS. These detectors exhibit single-photon sensitivity from the visible to mid-wave infrared and have enabled several new NASA space LiDAR applications. In this paper, we first report on the issue of mitigating dark counts due to “ROIC glow.” By introducing a revised light-barrier in our detector design, we demonstrate a near factor of 4 reduction in glow-induced dark counts. We further present direct measurements of excess noise factor and describe post-analysis models that accurately extract this quantity from focal plane array performance data. All methods consistently reveal excess noise factors well below the McIntyre limit. Gain measurements are conducted on a smaller-format avalanche photodiode array and reveal gains of ~6100 (measured at a reverse bias of 14.9 V, operating temperature of 84 K and using a 1.55 µm illumination source), which is a new record for the mid-wave infrared technology at Leonardo DRS. Additional performance metrics such as false-event rate, photon-detection efficiency and timing jitter are presented for larger-format arrays (i.e. arrays with a greater number of pixels). We conclude with an examination of a non-fundamental, injection contact-induced breakdown phenomenon. Experimental data and modeling reveal that this breakdown is dependent on the gain and the photon signal level, and unrelated to classical avalanche breakdown.

• Publisher: Springer Nature B.V
• Subject: Arrays / Avalanche diodes / Breakdown / Efficiency / Electron avalanche / Focal plane devices / Format / Mars / Noise factor / Operating temperature / Performance measurement / Photodiodes / Photons / Sensors / Space applications / Timing jitter