Monolithic integration of an infrared photon detector with a MEMS-based tunable filter

• Published in: IEEE electron device letters Vol. 26; no. 12; pp. 888 - 890
• Main Authors: Musca, C.A., Antoszewski, J., Winchester, K.J., Keating, A.J., Nguyen, T., Silva, K.K.M.B.D., Dell, J.M., Faraone, L., Mitra, P., Beck, J.D., Skokan, M.R., Robinson, J.E.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.12.2005; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Bragg; Circuit properties; Design. Technologies. Operation analysis. Testing; Detectors; Devices; Electric, optical and optoelectronic circuits; Electromagnetic spectrum; Electronic circuits; Electronics; Exact sciences and technology; Focal plane; Frequency filters; Infrared; infrared (IR); Infrared detectors; Infrared spectra; Integrated circuits; Intermetallics; Micro- and nanoelectromechanical devices (mems/nems); microelectromechanical system (MEMS); Microelectromechanical systems; Micromechanical devices; Monolithic integrated circuits; Optical device fabrication; Optical filters; Optoelectronic devices; Photoconducting devices; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Sensors; Silicon nitride; Space technology; tunable; Tuning; Integrated optics; Tunable circuit; Barrier layer; Bragg; detectors; microelectromechanical system (MEMS); Voltage control; tunable; Cavity; Optoelectronic device; Air gap; Monolithic integrated circuit; infrared (IR); Microelectromechanical device; Sacrificial layer; Focal plane arrays; Measurement sensor; Infrared detector; Two dimensional model; Narrow band; Photodetector; Near infrared radiation; Photoconducting device; Optical filter; silicon nitride; Manufacturing process; Tunable filter; Thermal imaging
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2005.859651

The monolithic integration of a low-temperature microelectromechanical system (MEMS) and HgCdTe infrared detector technology has been implemented and characterized. The MEMS-based tunable optical filter, integrated with an infrared detector, selects narrow wavelength bands in the range from 1.6 to 2.5 μm within the short-wavelength infrared (SWIR) region of the electromagnetic spectrum. The entire fabrication process is compatible with two-dimensional infrared focal plane array technology. The fabricated device consists of an HgCdTe SWIR photoconductor, two distributed Bragg mirrors formed of Ge-SiO-Ge, a sacrificial spacer layer within the cavity, which is then removed to leave an air gap, and a silicon nitride membrane for structural support. The tuning spectrum from fabricated MEMS filters on photoconductive detectors shows a wide tuning range, and high percentage transmission is achieved with a tuning voltage of only 7.5 V. The full-width at half-maximum ranged from 95 to 105 nm over a tuning range of 2.2-1.85 μm.