**6. Results and discussion**

The deformation surface of the membrane when a pressure of 25 kPa is applied to it, in the absence of packaging stresses, the maximum deflection is 3.64 × 10<sup>−</sup><sup>8</sup> m and the minimum deflection is 2.58 × 10<sup>−</sup><sup>8</sup> m (**Figure 8**).

**Figure 8.** *Surface of the deformation membrane when applied voltage is 25 kPa.*

#### **Figure 9.**

*Electric potential in the sealed chamber, plotted on a slice between the two plates of the capacitor.*

#### **Figure 10.**

*Displacement of the membrane as a function of the applied pressure.*

**Figure 9** shows the surface potential on a plane located between the plates. The potential is almost uniform and the value is near to 0.3 V.

In **Figure 10**, the simulated median and maximum displacements of the membrane as a function of applied pressure. At an applied pressure of 10 kPa, the *Electromechanical Analysis (MEMS) of a Capacitive Pressure Sensor of a Neuromate Robot Probe DOI: http://dx.doi.org/10.5772/intechopen.88946*

**Figure 11.** *Capacitance of the membrane as a function of applied pressure.*

diaphragm displacement in the center is 0.15 μm. The mean displacement of the diaphragm is 0.5 μm. These results indicate the mean diaphragm and the maximum diaphragm results are very close which increases the stability of the sensor.

**Figure 11** shows that the capacitance of the device increases nonlinearly with applied pressure.

At zero applied pressure the sensitivity of the model (quarter of the whole sensor) is 7.4 × 10<sup>−</sup><sup>6</sup> pF/Pa. The device sensitivity is therefore 7.4 × 10<sup>−</sup><sup>6</sup> pF/Pa.

The capacitance without package stress is less than the analytic capacitance but the capacitance with package stress is greater than the analytic capacitance.
