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Proceedings Paper

Crosstalk study of near infrared InGaAs detectors
Author(s): Xue Li; Hengjing Tang; Tao Li; Cui Fan; Xiumei Shao; Jianwei Li; Jun Wei; Haimei Gong
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Paper Abstract

Crosstalk characteristics of high density FPA detectors attract widespread attention in the application of electro-optical systems. Crosstalk characteristics of near-infrared (NIR) InGaAs photodiodes and focal plane arrays (FPAs) were studied in this paper. The mesa type detector was investigated by using laser beam induced current technique (LBIC) to measure the absorption outside the designed photosensitive area, and the results show that the excess absorption enlarges the crosstalk of the adjacent pixels. The structure optimization using the effective absorption layer between the pixels can effectively reduce the crosstalk to 2.5%. The major crosstalk components of the optimization photodiode come from the electronic signal caused by carrier lateral diffusion. For the planar type detectors, test structures were used to compare the crosstalk of different structures, and the guard ring structure shows good suppression of the crosstalk. Then the back-illuminated 32x32 InGaAs photodiodes with 30μm pitch were designed, and LBIC was used to measure its lateral diffusion of the effective carriers and fill factor of photosensitive area. The results indicate that the fill factor of detectors can reach up to 98% when the diffusion region is optimized, and the minimum response exists between two neighborhood pixels. Based on these crosstalk measurement results and optimizing structure designs, the linear InGaAs photodiodes were designed and thus the InGaAs FPA assembly was fabricated. The assembly shows higher electro-optical performance and good improvement on crosstalk. The assembly was applied in infrared imaging system and modulation transfer function (MTF) of FPA assembly was calculated to be above 0.50. The clear image based on FPA assembly was obtained.

Paper Details

Date Published: 20 May 2016
PDF: 7 pages
Proc. SPIE 9819, Infrared Technology and Applications XLII, 98192A (20 May 2016); doi: 10.1117/12.2222736
Show Author Affiliations
Xue Li, Shanghai Institute of Technical Physics (China)
Hengjing Tang, Shanghai Institute of Technical Physics (China)
Tao Li, Shanghai Institute of Technical Physics (China)
Cui Fan, Shanghai Institute of Technical Physics (China)
Xiumei Shao, Shanghai Institute of Technical Physics (China)
Jianwei Li, Shanghai Institute of Technical Physics (China)
Jun Wei, Shanghai Institute of Technical Physics (China)
Haimei Gong, Shanghai Institute of Technical Physics (China)

Published in SPIE Proceedings Vol. 9819:
Infrared Technology and Applications XLII
Bjørn F. Andresen; Gabor F. Fulop; Charles M. Hanson; Paul R. Norton, Editor(s)

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