Design considerations in micromachined silicon microphones

We present and compare the different designs of micromachined silicon condenser microphones. The aim is to develop the microphones with high sensitivity and low fabrication cost. Slotted and corrugated diaphragms have been designed and fabricated in order to increase the mechanical sensitivity of microphones. At the same time, we developed the fabrication process for the low stress or stress-free multilayers polysilicon used as the microphone diaphragms. To increase the microphone chip density on one wafer and avoid the sticking problem during the wet release process, a new process design using deep reactive ion etching is proposed, which is available in our laboratory. (C) 2002 Published by Elsevier Science Ltd.