Trade-off between sensitivity and dynamic range in designing MEMS capacitive pressure sensor

Capacitive pressure sensors can be used for touch mode applications with pressure ranging from 0.05 MPa to 2 MPa. This paper provides the information about the variation in dynamic range of a MEMS capacitive pressure sensor when its sensitivity is improved. The shape of the capacitive pressure sensor diaphragm is changed from normal flat diaphragm to a centre bossed structure and was found that Bossed diaphragm membranes improves the central deflection sensitivity but the range was limited. MEMS Capacitive pressure sensor with normal diaphragm and diaphragm with centre boss structure is designed and analysed using multiphysics tool and it is found that while the sensitivity is increased by 0.92µm/KPa but the range is reduced by 20KPa for the bossed diaphragm.