What are the design considerations in selection of MEMS materials ?

• In recent years, enormous progress has been made in the design, fabrication 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 micro-electronics, 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 three 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 metric based on material properties such as young's modulus, density strength etc.

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