Capacitive microphone fabricated with CMOS-MEMS surface-micromachining technology

This paper presents a standard complementary metal-oxide-semiconductor (CMOS) technology combined with sacrificial layers etching used for micro-electro-mechanical systems (MEMS) fabrication. We will describe the modeling and the design of an acoustic device represented here by a condenser microphone with a perforated diaphragm. Models based on the electromechanical analogy and on the finite element analysis (FEA) have been used to predict the behavior of the microphone. These models have taken into account material constants and dimensions of the AMS 0.35 μm CMOS technology. An effect of etch holes in the microphone diaphragm on the dynamic response of the structure was studied and an optimization study has been done to determine the sensor lateral dimensions and the position of these holes. We will show simulation results, the microphone design and the final layout of the structure.