CMOS-MEMS membrane for audio-frequency acoustic actuation

Using CMOS-MEMS micromachining techniques we have constructed a prototype earphone that generates audible acoustic output from 40 Hz to 10 kHz. The fabrication of the acoustic membrane consists of only two additional steps subsequent to the prior post-CMOS micromachining steps developed at Carnegie Mellon University [Sens. Actuat. A 57 (1996) 103-110]. The ability to build a membrane directly within a standard CMOS chip, integrating mechanical structures with signal processing electronics will enable a variety of applications including economical earphones, microphones, hearing aids, high-fidelity earphones, cellular phones and noise cancellation earphones and devices. (C) 2002 Elsevier Science B.V. All rights reserved.