Reliability and Fatigue Analysis in Cantilever-Based MEMS Devices Operating in Harsh Environments

Table 2

Mechanical failures.

Mechanical fracture
Failure	Overload	Shock	Corrosion	Fatigue
Causes	Excessive stress	Drops, excessive loading, and mechanical interference disorder	Chemical reaction, oxidation	Structural damage at cyclic loading
Stiction
Failure	Vander Waals forces	Capillary forces	Chemical bonding	Electrostatic charging	Residual stress
Causes	Interaction of atoms or molecules at the surface of close contact	Monolayer of water on all surfaces that lubricates the surface inducing capillary force	Chemical bond between contacting surfaces	Two closed surfaces at different potentials	During the release process structure tends to bend or deform
Wear
Failure	Adhesion	Abrasion	Corrosion	Surface fatigue
Causes	Pulling off fragments of another surface while sliding due to surface forces between them	Stripping away material from soft surface while sliding of harder surface	When two surfaces chemically interact	Smooth surfaces are subjected to cyclic loading instead of sliding
Creep and fatigue
Failure	Intrinsic stress	Applied stress	Thermal stress
Causes	Residual stress	Input load	Overheating