Design of High Performance Condenser Microphone Using Porous Silicon

S. Suganthi[1], M. Anandraj[2], and L. Sujatha[1]
[1]Department of Electronics & Communication Engineering, Rajalakshmi Engineering College, Chennai, India
[2]Department of Physics, Rajalakshmi Engineering College, Chennai, India
Published in 2010

Porous Silicon (PS) can easily be formed by electrochemical etching of silicon in HF based electrolytes at room temperature. Since, PS is compatible with silicon IC technology; it finds lot of applications in the fabrication of MEMS devices. In the current study, we discuss the design of a condenser microphone using a Silicon/ Porous Silicon composite membrane as a movable plate. The performance analysis of this structure has been carried out by COMSOL. Simulation was carried out for condenser microphone with PS membrane and it has been compared to condenser microphone with silicon membrane. We find that the capacitance obtained using PS membrane is 1.52 times more than that of condenser microphone with pure silicon membrane for an applied load of 50 Pa. Then the performance of Si/PS composite membrane for condenser microphone has been discussed. It is found that the capacitance obtained on Si/PS composite membrane increases with PS layer thickness for the same applied pressure.

Download