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Journal of Micro/Nanolithography, MEMS, and MOEMS • Open Access

Design and fabrication of resonator-quantum well infrared photodetector for SF6 gas sensor application
Author(s): Jason Sun; Kwong-Kit Choi; Eric DeCuir; Kimberley Olver; Richard Fu

Paper Abstract

The infrared absorption of SF6 gas is narrowband and peaks at 10.6  μm. This narrowband absorption posts a stringent requirement on the corresponding sensors as they need to collect enough signal from this limited spectral bandwidth to maintain a high sensitivity. Resonator-quantum well infrared photodetectors (R-QWIPs) are the next generation of QWIP detectors that use resonances to increase the quantum efficiency for more efficient signal collection. Since the resonant approach is applicable to narrowband as well as broadband, it is particularly suitable for this application. We designed and fabricated R-QWIPs for SF6 gas detection. To achieve the expected performance, the detector geometry must be produced according to precise specifications. In particular, the height of the diffractive elements and the thickness of the active resonator must be uniform, and accurately realized to within 0.05  μm. Additionally, the substrates of the detectors must be completely removed to prevent the escape of unabsorbed light in the detectors. To achieve these specifications, two optimized inductively coupled plasma etching processes were developed. Due to submicron detector feature sizes and overlay tolerance, we used an advanced semiconductor material lithography stepper instead of a contact mask aligner to pattern wafers. Using these etching techniques and tool, we have fabricated focal plane arrays with 30-μm pixel pitch and 320×256 format. The initial test revealed promising results.

Paper Details

Date Published: 1 September 2017
PDF: 7 pages
J. Micro/Nanolith. MEMS MOEMS 16(3) 034504 doi: 10.1117/1.JMM.16.3.034504
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 16, Issue 3
Show Author Affiliations
Jason Sun, U.S. Army Research Lab. (United States)
Kwong-Kit Choi, U.S. Army Research Lab. (United States)
Eric DeCuir, U.S. Army Research Lab. (United States)
Kimberley Olver, U.S. Army Research Lab. (United States)
Richard Fu, U.S. Army Research Lab. (United States)

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