A Little Knowledge

This article explains microelectromechanical systems (MEMS) design concepts that are under investigation for their application in different domains. MEMS provide numerous performance advantages. Miniaturization improves packaging and simplifies installation and maintenance. Power consumption can drop dramatically. Analysis shows that appropriate hermeticity and cleanliness remain a challenge, because sufficient contamination to introduce frequency drift may result from the migration of trace contaminants within a package itself. Many reliability issues apply to different MEMS in diverse ways. Work to date indicates that low-stress, hermetically packaged devices pose little concern about crack growth. The increasing maturity of MEMS and the emphasis on reliability represents good news for the industry, as it reflects the natural evolution from initial product design to fabrication technologies to long-term reliability. Despite current challenges, there is no fundamental constraint to reliability improvements as our knowledge of failure mechanisms and countermeasures increases.