MEMS stress sensor

QuickField simulation example

MEMS sensor changes its shape under mechanical stress. The electrode plates come close and the variation in electrical capacitance is detected.

Problem Type
Plane-parallel problem of electrostatics and stress analysis .

Geometry

Given

Task
Calculate the sensor deformation and electrical capacitance in initial and deformed states.

Solution
Initially the electrostatic problem is simulated to calculate the native capacitance of the sensor.
Then deformed sensor profile is calculated in stress analysis problem. The profile is exported into the separate geometry model file using Stress Deform tool. That deformed shape model is then used to run another electrostatic analysis to calculate the deformed state capacitance.

Results
Initial capacitance value 0.0026 pF
Capacitance in deformed state 0.0028 pF (+10%)

Electric field distribution in the deformed stress sensor

• Video: MEMS stress sensor. Watch on YouTube.
  Calculation of deformed shape using QuickField Stress Analysis module
  
  Translation of the deformed shape to the geometry model using the StressDeform tool
  
  Initial capacitance calculation using Electrostatics module.
  
  Deformed state capacitance calculation
  
• View simulation report in PDF
• Download simulation files (files may be viewed using any QuickField Edition).