Surface and Bulk Micromachined Dual Back-Plate Condenser Microphone – IEEE Jan 2005

This paper presents the design, fabrication, and characterization of a dual back-plate condenser microphone. The microphone was designed for aeroacoustic applications where a high dynamic range and high bandwidth are key requirements. It was fabricated using the SUMMiT V process at Sandia National Laboratories. The microphone has a 2.25 um thick circular diaphragm with a 230 um radius and 2 um gap between each back-plate. The device has demonstrated a sensitivity of 282 uV/Pa, a linear response up to 160 dB, a noise floor of 42 dBSPL at 1 kHz in a 1 Hz bin, and a flat frequency response up to 20 kHz; the theoretical bandwidth exceeds 100 kHz.

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