The sensitivity of a silicon condenser microphone, which essentially consists of a rigid backplate and a thin movable diaphragm, mainly depends on diaphragm performance. There is the possibility to use diaphragms working either in a membrane or in a plate mode, with tensile forces or bending forces governing the sensitivity to sound pressure respectively. In this study, the numerical simulation of a reinforced polysilicon thin plate is conducted in order to optimize the overall performance of a MEMS condenser microphone. The geometrically nonlinear finite-element method is adopted to analyze the mechanical sensitivity of the diaphragm, and stress stiffening is included in the analysis since the out-of-plane stiffness of the diaphragm can be drastically affected by the state of in-plane residual stresses [1]. The influence on the diaphragm performance of reinforcement parameters and the material residual stresses are studied, and optimum geometric designs are determined to accomplish a range of microphone specifications.
TOPOLOGY OPTIMIZATION OF REINFORCED POLYSILICON
Colpo, Sabrina;Mulloni, Viviana;Giacomozzi, Flavio;Margesin, Benno
2008-01-01
Abstract
The sensitivity of a silicon condenser microphone, which essentially consists of a rigid backplate and a thin movable diaphragm, mainly depends on diaphragm performance. There is the possibility to use diaphragms working either in a membrane or in a plate mode, with tensile forces or bending forces governing the sensitivity to sound pressure respectively. In this study, the numerical simulation of a reinforced polysilicon thin plate is conducted in order to optimize the overall performance of a MEMS condenser microphone. The geometrically nonlinear finite-element method is adopted to analyze the mechanical sensitivity of the diaphragm, and stress stiffening is included in the analysis since the out-of-plane stiffness of the diaphragm can be drastically affected by the state of in-plane residual stresses [1]. The influence on the diaphragm performance of reinforcement parameters and the material residual stresses are studied, and optimum geometric designs are determined to accomplish a range of microphone specifications.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
