Simulation and optimization of a micro-machined silicon condenser microphone using a perforated diaphragm

A method was proposed to analyze silicon condenser microphone using a perforated diaphragm. Different from the microphone with back-holes, the acoustic holes are made on the diaphragm, which avoids making the holes on the back plate and etching the back chamber. For the microphone with this structure, a new analysis method was proposed, which combines the microphone equivalent circuit and finite element analysis, establish a more accurate microphone equivalent circuit. On this basis, we studied the effects of diaphragm area, microphone acoustic hole and air gap on the microphone performance, which can provide the theoretical guidance for the design of microphone. Finally, the steepest descent is used to optimize the structure of the microphone. The sensitivity of the optimized structure is -41.6dB with the pull-in voltage is 12V, and the frequency response in 20Hz-20.6kHz is flat.