An Introduction to mems (Micro-electromechanical Systems)

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In order to protect MEMS devices from external contamination as well as enable them to 

dissipate generated heat, thin-film coatings can be deposited on the components.  In a process 

called passivation using plasma enhanced chemical vapour deposition (PECVD), thin-film 

coatings of usually silicon dioxide or silicon nitride increase wear resistance and electrical 

insulation. 

Encapsulation is used to protect the sensor die against adverse influences from the 

epoxies, silicones and polyurethanes.  These materials need to adhere well to the substrate, be 

crack free and minimize induced mechanical stress as well as stresses due to mismatching of 

thermal expansion coefficients.