Design and Characterization of a Micro-Fabricated Graphene-Based MEMS Microphone

Graham Wood, Alberto Torin, Asaad Kareem Edaan Al-Mashaal, Leslie Smith, Enrico Mastropaolo, Michael J. Newton, Rebecca Cheung

Research output: Contribution to journalArticlepeer-review

Abstract

We fabricate a MEMS microphone that incorporates a graphene-based membrane that vibrates in response to acoustic forcing. We employ a novel fabrication process, where a graphene/PMMA bilayer membrane is transferred over a cavity on a separate chip before being affixed to the surface of another chip containing an electrode, resulting in the fabrication of a moveable capacitor with a membrane-to-electrode gap of 8 µm. The gap, which is less than half the size of other reported graphene membrane-based audio transducers, allows for the device to operate with low DC bias voltages of about 1 V and, when integrated with a custom-designed readout circuit, demonstrates a sensitivity to sound pressure between 0.1 mV/Pa and 10 mV/Pa across the range 100 Hz to 20 kHz. As well as a sensitivity that is comparable to previous work, the flat frequency response is stable when the sound pressure is varied between 70dBSPL and 80dBSPL, with the sensitivity value not varying by more than 0.2 mV/Pa.
Original languageEnglish
Pages (from-to)7234-7242
Number of pages9
JournalIEEE Sensors Journal
Volume19
Issue number17
Early online date1 May 2019
DOIs
Publication statusPublished - 1 Sep 2019

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