• In recent years, enormous progress and commercialization of Microsystems.
• Associated with these advances is an expansion of the set of materials available to MEMS designers.
• In addition to the materials traditionally used in silicon microelectronics, it is now possible to introduce and integrate a wide variety of metals and alloys, ceramics and glasses and polymers and elastomers.
• This capability motivates the following question, given a design concept, how is a designer to choose a material or set of materials to optimize performance and reliability.
• There are 3 requirements for materials to be used in MEMS.

1) Compatibility with silicon technology.

2) Desirable electromechanical properties.

3) Low values of residual stresses.

• Materials should be selected for applications based on measurable criteria.

• It is possible to compare the suitability of materials for a given application according to quantifiable performance metrics based on material properties such as young's modulus, density, strength, etc.

• Some material properties such as scale, role of manufacturing, microstructures fiber composite allow flexibility are more invariant than others.