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

Scheeper, P.R. and Olthuis, W. and Bergveld, P. (1994) Improvement of the performance of microphones with a silicon nitride diaphragm and backplate. Sensors and Actuators A: Physical, 40 (3). pp. 179-186. ISSN 0924-4247

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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).
Item Type:	Article
Copyright:	© 1994 Elsevier Science
Faculty:	Electrical Engineering, Mathematics and Computer Science (EEMCS)
Research Group:	Biomedical and Environmental Sensor systems (BIOS)
Link to this item:	http://purl.utwente.nl/publications/15073
Official URL:	http://dx.doi.org/10.1016/0924-4247(94)87003-9
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