Analytical Characterisation of Piezoresistive Square Diaphragm Silicon Microphone

Journal article, 1996

An analytical energy method has been used to derive the characteristics of a square-diaphragm piezoresistive silicon microphone. All relevant mechanical and acoustical effects of the sensor characteristics are included in the method. First, the energy contributions are calculated and then identified with equivalent acoustical impedances. These equivalent impedances are used in the electrical analogy. The method is applied to a piezoresistive microphone having a square diaphragm over its cavity. A special vent channel which equalizes the static air pressure between the cavity and the ambient has been included in the model. Good agreement between the theoretical analysis and experimental data on fabricated microphones was obtained.