Frequency softening of an electrostatically actuated beam

Author

Parmeshwar Prasad

Date

Nov 29, 2014 2:53:53 AM

Company

CeNSE

Version

3

Summary

Frequency softening of an electrostatically actuated fixed-fixed Silicon

Nitride beam structure is studied.

Contents
1. Global Definitions
1.1. Parameters 1
2. Component 1 (comp1)
2.1. Definitions
2.2. Geometry 1
2.3. Materials
2.4. Electromechanics (emi)
2.5. Mesh 1
3. bias
3.1. Parametric Sweep
3.2. Stationary
3.3. Eigenfrequency
4. Results
4.1. Data Sets
4.2. Derived Values
4.3. Tables
4.4. Plot Groups

1. Global Definitions

1.1. Parameters 1

Parameters
Name Expression Description
W1 1[um] width
L1 10[um] length of the beam
L2 40[um] length of the pads
W2 1[um] width of the pads
T1 1[um] thickenss of the beam and substrate
T2 2[um] thickness of the pads
Vdc 200[V] DC Voltage appliead

2. Component 1 (Comp1)

2.1. Definitions

2.1.1. Selections

OuterContactPads
Selection type
Explicit
Selection
Domains 3, 14
InnerContactPads
Selection type
Explicit
Selection
Domains 6, 11
BoundaryInnerContactPads
Selection type
Adjacent
Selection
Boundaries 23–26, 35, 38, 52–55, 66, 69
BoundaryouterContactPads
Selection type
Adjacent
Selection
Boundaries 9–12, 14, 16, 74–77, 79, 81
SiN
Selection type
Explicit
Selection
Domains 2, 4–5, 7–10, 12–13
PolySi
Selection type
Explicit
Selection
Domains 3, 6, 11, 14
Air
Selection type
Explicit
Selection
Domain 1

2.1.2. Coordinate Systems

Boundary System 1
Coordinate system type Boundary system
Identifier sys1

2.2. Geometry 1

geom_geom1.png

Geometry 1

Units
Length unit µm
Angular unit deg

2.3. Materials

2.3.1. Air

materialmat3.png

Air

Selection
Geometric entity level Domain
Selection Domain 1

2.3.2. Poly-Si

materialmat4.png

Poly-Si

Selection
Geometric entity level Domain
Selection Domains 3, 6, 11, 14

2.3.3. Si3N4

materialmat5.png

Si3N4

Selection
Geometric entity level Domain
Selection Domains 2, 4–5, 7–10, 12–13

2.4. Electromechanics (Emi)

physics_emi.png

Electromechanics

Features
Free Deformation 1
Electrical Material Model 1
Zero Charge 1
Free 2
Electromechanical Interface 1
Prescribed Mesh Displacement 1
Linear Elastic Dielectric 1
Initial Values 1
Linear Elastic Material 1
Fixed Constraint 1
Fixed Mesh 2
Electric Potential 1
Electric Potential 2

2.5. Mesh 1

mesh_mesh1.png

Mesh 1

3. Bias

3.1. Parametric Sweep

Parameter name: Vdc

Parameters:

3.2. Stationary

Study settings
Property Value
Include geometric nonlinearity On
Mesh selection
Geometry Mesh
Geometry 1 (geom1) mesh1
Physics selection
Physics Discretization
Electromechanics (emi) physics

3.3. Eigenfrequency

Study settings
Property Value
Include geometric nonlinearity On
Mesh selection
Geometry Mesh
Geometry 1 (geom1) mesh1
Physics selection
Physics Discretization
Electromechanics (emi) physics

4. Results

4.1. Data Sets

4.1.1. Solution 1

Solution
Name Value
Solution Solver 1
Component Save Point Geometry 1

dataset_dset1.png

Data set: Solution 1

4.1.2. Solution 2

Solution
Name Value
Solution Store Solution 2
Component Save Point Geometry 1

dataset_dset2.png

Data set: Solution 2

4.1.3. Solution 3

Solution
Name Value
Solution Parametric 3
Component Save Point Geometry 1

dataset_dset3.png

Data set: Solution 3

4.2. Derived Values

4.2.1. Global Evaluation 1

Data
Name Value
Data set Solution 3
Expression
Name Value
Expression emi.freq
Unit Hz
Description Frequency

4.3. Tables

4.3.1. Evaluation 3D

Interactive 3D values

Evaluation 3D
x y z Value
6 1.09769 2.07095 1.91234e-20

4.3.2. Table 1

Global Evaluation 1 (emi.freq)

Table 1
Vdc Frequency (Hz)
0 5.279e6
50 5.26937e6
100 5.24075e6
150 5.19399e6
200 5.13047e6
250 5.05203e6
300 4.96082e6
350 4.85899e6
400 4.74816e6

4.4. Plot Groups

4.4.1. Displacement (Emi)

plotgroup_pg7.png

Vdc(4)=150 Eigenfrequency=5.193995e6 Surface: Total displacement (µm)

4.4.2. Potential (Emi)

plotgroup_pg8.png

Vdc(4)=150 Eigenfrequency=5.193995e6 Slice: Electric potential (V) Streamline: Displacement field (Material) Contour: Electric potential (V)

4.4.3. 1D Plot Group 9

plotgroup_pg9.png