Development of a CMOS-compatible process for a silicon miniature microphone with high sensitivity

In this paper, a CMOS compatible process for high sensitive silicon micron microphone has been proposed. Corrugated diaphragms have been introduced to reduce the initial stress. A MOS preamplifier with very high input impedance can be integrated in the same chip to meet the requirement on high output sensitivity, low power consumption and minimization. As a matter of fact, the polysilicon of the composite diaphragm can be patented as resistors and gates of MOSFET. All the CMOS process steps except the N well implantation and drive in can be placed after the microphone fabrication. This process is simple, efficient and seems very promising for future miro-acoustic systems.