Improvement of the performance of microphones with a silicon nitride diaphragm and backplate

P.R. Scheeper, W. Olthuis, P. Bergveld

    Research output: Contribution to journalArticleAcademicpeer-review

    43 Citations (Scopus)
    142 Downloads (Pure)

    Abstract

    The performance of a single-wafer fabricated silicon condenser microphone has been improved by increasing the stress and the acoustic hole density of the backplate and by decreasing the diaphragm thickness. The best microphones show a sensitivity of 5.0 mV Pa−1, which corresponds to an open-circuit sensitivity of 10 mV Pa−1 for a microphone capacitance of 6.6 pF. The measured frequency response is flat within ±2 dB from 100 Hz to 14 kHz, which is better than the requirements for a hearing-aid microphone. The operating voltage of these microphones is only 5.0 V, which is about 60% of the collapse voltage. The measured noise level of the microphones is 30 dBA SPL, which is approximately as low as required for a hearing-aid microphone ( <29.5 dBA SPL).
    Original languageEnglish
    Pages (from-to)179-186
    JournalSensors and actuators. A: Physical
    Volume40
    Issue number3
    DOIs
    Publication statusPublished - 1994

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