Investigation of the effect of diaphragm thickness on the sensitivity of silicone capacitive pressure sensor

Capacitive pressure sensors are widely used in industrial processes and manufacturing industries. Capacitive sensors are highly regarded for advanced sensors due to their high sensitivity,low noise and fast response to pressure. These sensors are capable of withstanding high vibration and these are always considered in designs because these have high stability in temperature variations.Considering the diaphragm behavior is essential for mechanical sensors designing such as pressure sensors.This paper examines the effect of diaphragm diameter on the sensitivity of the pressure sensor. Accordingly, displacement for a diaphragm with a diameter of 1um, 1.6um, 2.2um at a pressure of 20KPa was 1.5um, 1um, 0.5um respectively. Also alteration of capacitive volume based on temperature and pressure variations have been evaluated from 0 to 120KPa for this sensor. The results demonstrate that the capacitance increases with the increasing in pressure at the diaphragm surface and decreases with increasing temperature both nonlinearly. Also, the stress increases with increasing the operating temperature and applied pressure on the diaphragm nonlinearly.

Keywords:

diaphragm , sensors , capacitive pressure sensor , micro electromechanical systems