Title :
Analytical analysis and finite element simulation of advanced membranes for silicon microphones
Author :
Füldner, Marc ; Dehé, Alfons ; Lerch, Reinhard
Author_Institution :
Infineon Technol. AG, Munich, Germany
Abstract :
In this paper, advanced membrane designs are simulated in order to improve the sensitivity of micromachined silicon condenser microphones. Analytical analyzes and finite element simulations have been carried out to derive algebraic expressions for the mechanical compliance of corrugated membranes and membranes supported at spring elements. It is shown that the compliance of both types of membranes can be modeled with the help of an enhanced theory of circular membranes. For spring membranes, a numerically derived and design dependent constant takes into account the reduced suspension. The mechanical stress in corrugated membranes is calculated using a geometrical model and is confirmed by finite element simulations. A very good agreement between theory and experimental results is demonstrated for spring membranes of different shape and for membranes with varying number of corrugations. In a silicon microphone application, a high electro-acoustical sensitivity up to 8.2 mV/Pa/V is achieved with a membrane diameter of only 1 mm.
Keywords :
algebra; finite element analysis; internal stresses; micromechanical devices; microphones; sensitivity; silicon; 1 mm; advanced membrane designs; algebraic expressions; circular membranes; corrugated membranes; electro-acoustical sensitivity; finite element simulation; geometrical model; internal stresses; mechanical compliance; mechanical stress; micromachined silicon condenser microphones; micromechanical devices; silicon microphones; spring elements; spring membranes; Analytical models; Biomembranes; Brushless DC motors; Electrets; Finite element methods; Microphones; Silicon; Solid modeling; Springs; Stress; Corrugated membrane; finite element method (FEM); modeling; silicon microphone; spring membrane;
Journal_Title :
Sensors Journal, IEEE
DOI :
10.1109/JSEN.2004.841449