Title :
A fully-integrated CMOS-MEMS audio microphone
Author :
Neumann, J.J., Jr. ; Gabriel, K.J.
Author_Institution :
Dept. of Electr. & Comput. Eng., Carnegie Mellon Univ., Pittsburgh, PA, USA
Abstract :
We report on the construction of a microphone and associated electronics fabricated entirely within a standard CMOS (complementary metal oxide semiconductor) die. An A-weighted noise level of 46 dB SPL was achieved with a total diaphragm area of 0.61 mm/sup 2/. Because the microphone uses the same processing sequence as CMOS-MEMS (microelectromechanical systems) microspeakers it is now possible to create acoustic systems-on-chip for applications in such areas as hearing aids, in-ear translators, and active noise cancellation. Because electret materials are not used, the microphone can withstand temperatures up to 250/spl deg/C with no degradation in performance. The frequency-modulated output provides a convenient, low-noise way to transmit the signal off chip, and is directly compatible with digital circuitry and FM radios.
Keywords :
CMOS integrated circuits; acoustic noise; diaphragms; electrets; frequency modulation; hearing aids; loudspeakers; micromechanical devices; microphones; radio receivers; system-on-chip; 46 dB; CMOS die; FM radios; acoustic systems-on-chip; active noise cancellation; complementary metal oxide semiconductor; diaphragm area; digital circuitry; electret materials; frequency-modulated output; hearing aids; in-ear translators; integrated CMOS-MEMS audio microphone; microelectromechanical systems; microspeakers; noise level; signal off chip; Acoustic applications; Degradation; Electrets; Hearing aids; Microelectromechanical systems; Microphones; Noise cancellation; Noise level; Radiofrequency integrated circuits; Temperature;
Conference_Titel :
TRANSDUCERS, Solid-State Sensors, Actuators and Microsystems, 12th International Conference on, 2003
Conference_Location :
Boston, MA, USA
Print_ISBN :
0-7803-7731-1
DOI :
10.1109/SENSOR.2003.1215295
