Fabrication, electrical characterization and sub-ng mass resolution of sub-μm air-gap bulk mode MEMS mass sensors for the detection of airborne particles

Autor: Charles Motzkus, Frederic Marty, Ugur Soysal, Emmanuelle Algre, Evelyne Gehin
Přispěvatelé: Centre d'Etudes et Recherches en Thermique, Environnement et Systèmes [Créteil] (CERTES EA 3481), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Electronique, Systèmes de communication et Microsystèmes (ESYCOM), Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Université Paris-Est Marne-la-Vallée (UPEM)-ESIEE Paris, Conservatoire National des Arts et Métiers [CNAM] (CNAM), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Université Paris-Est Marne-la-Vallée (UPEM)-ESIEE Paris, Centre Scientifique et Technique du Bâtiment (CSTB)
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Microelectronic Engineering
Microelectronic Engineering, Elsevier, 2020, 221, pp.111190-. ⟨10.1016/j.mee.2019.111190⟩
ISSN: 0167-9317
1873-5568
Popis: In this study, we propose to realize high-performance inertial Micro-Electro-Mechanical Systems (MEMS) mass sensors by the thick oxide as a mask layer fabrication technique. This method enables to reduce the air-gap to sub-μm in capacitively transduced MEMS with optical lithography and has been used to fabricate high aspect ratio sub-μm air-gap bulk mode MEMS mass sensors. MEMS devices have been designed and fabricated with the gap size as small as ~400 nm for ~38 μm thick SOI-based resonators (~95:1). Due to the conical characteristic of the gap, the mean air-gap has also been estimated as ~868 nm with 46 μm depth, which results in ~ 53:1 aspect ratio for the silicon test wafers that have been treated under the same conditions with the SOI-based devices. COMSOL simulation results and fabricated MEMS resonators coherently show that MEMS devices exhibit Lame mode at 4.099 MHz resonance frequency with the estimated quality factor around 20,000, and extensional mode at 4.467 MHz with the estimated quality factors around 18,000 in the air. The motional resistance has been estimated as small as 27.28 Ω for the Lame mode operating at 40 V. In this study, two different bulk modes have been considered as sensitive and uniform mass sensors for the detection of airborne particles. Then, minimum mass measurement capability of both modes has been experimentally estimated as 0.51 ng and 0.47 ng for Lame and extensional modes, respectively. The latter, a proof-of-concept mass measurement has been conducted to deduce the resonance frequency shifts of both modes upon an added mass. This work demonstrates optimization of the thick oxide mask layer fabrication technique and realization of high aspect ratio bulk-mode MEMS mass sensors.
Databáze: OpenAIRE
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