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Infrared absorption sensor for multiple gas sensing. Development of a Fabry–Perot spectrometer with ultrawide wavelength range
Author(s) -
Enomoto Tetsuya,
Suzuki Megumi,
Iwaki Takao,
Wado Hiroyuki,
Takeuchi Yukihiro
Publication year - 2013
Publication title -
electronics and communications in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.131
H-Index - 13
eISSN - 1942-9541
pISSN - 1942-9533
DOI - 10.1002/ecj.10433
Subject(s) - spectrometer , fabry–pérot interferometer , materials science , wavelength , optics , etching (microfabrication) , microelectromechanical systems , absorption (acoustics) , refractive index , infrared , optoelectronics , layer (electronics) , physics , nanotechnology
Abstract We report on a novel MEMS (microelectromechanical system) based on a Fabry–Perot spectrometer with an ultrawide wavelength range (3.2 to 8.4 µm) compared to the previously reported ones (typically 2.8 to 5.8 µm). The wavelength range of a Fabry–Perot spectrometer is known to be increased by increasing the ratio of the refractive indexes of the multilayer mirrors. Thus, a novel mirror structure was proposed, replacing a low‐refractive‐index layer of SiO 2 ( n L = 1.44) by air ( n L = 1) for a wider wavelength range. The proposed device was fabricated by HF sacricial layer etching of SiO 2 between four ultrathin polysilicon lms (ca. 320 nm). The following two ideas were adopted to fabricate this delicate structure properly. (1) Electrostatic force was generated only in the outer region surrounding the air mirror so as not to deform the mirror. (2) A supercritical drying process was employed after the sacricial etching to prevent possible sticking issues. © 2013 Wiley Periodicals, Inc. Electron Comm Jpn, 96(5): 50–57, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10433