Short-Wave Infrared HgCdTe Electron Avalanche Photodiodes for Gated Viewing

• Published in: Journal of electronic materials 2018-10, Vol.47 (10), p.5705-5714
• Main Authors: Sieck, A., Benecke, M., Eich, D., Oelmaier, R., Wendler, J., Figgemeier, H.
• Format: Article
• Language: English
• Subjects: Background noise; Characterization and Evaluation of Materials; Chemistry and Materials Science; Clutter; Cut off wavelength; Electric potential; Electron avalanche; Electronics and Microelectronics; Focal plane devices; Image contrast; Image enhancement; Instrumentation; Integrated circuits; Materials Science; Mercury cadmium tellurides; Operating temperature; Optical and Electronic Materials; Photodiodes; Short wave radiation; Solid State Physics; U.S. Workshop on Physics and Chemistry of II-VI Materials 2017; U.S. Workshop on the Physics and Chemistry of II-VI Materials 2017; Viewing
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-018-6425-0

Short-wave infrared (SWIR) HgCdTe electron avalanche photodiodes (eAPDs) with different doping profiles have been characterized for use in SWIR gated viewing systems. Gated viewing offers enhanced image contrast in scenes with clutter from the foreground or background. HgCdTe-based eAPDs show exponential gain–voltage characteristics and low excess noise and are, therefore, well suited for active imaging applications. The gain achievable at a fixed reverse voltage varies with the bandgap of the Hg 1−x Cd x Te detector material. We analyze current–voltage and gain–voltage plots measured on SWIR Hg 1−x Cd x Te eAPDs with x  = 0.45, corresponding to a cutoff wavelength of 2.55  μ m at 150 K. The cutoff has been chosen as a trade-off between achievable APD gain and operating temperature for SWIR gated-viewing systems with target distances of about 1000 m. Focal plane arrays with a readout-integrated circuit featuring a fast internal clock have been built and their performance with respect to gated viewing applications has been evaluated on a laboratory demonstrator for short distances. Future plans for a field demonstrator for distances up to 1000 m are described briefly at the end.