Static model analysis. Proof mass, suspension beams, static deflection. Residual stress and Poisson’s ratio. Spring constants. Strain under acceleration. Sensitivity, thermal noise. Resolution due to the ADC. Maximum acceleration. Dynamic model analysis.
Аннотация к работе
In this work possible design of accelerometer, which can be produced using MOSIS 2 poly and 2 metal process, will be considered. To etch silicon under the proof mass post-process isotropic etching will be applied and some additional mass of Al will added by wire bonding in order to make total mass 10 times of the initial mass. It will be shown below that with such choice of beam structure piezoresistor’s polysilicon strain under acceleration 100g is lower then critical strain for polysilicon. So, in this work, because one type of material is used for beams influence of residual stress will be neglected (as it is done in previous section for deflection). From equations above it can be seen that total strain can be affected by stress in normal direction.