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 :-
Compatibility with silicon technology
Desirable electromechanical properties
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.