Materials issues in microelectromechanical devices: science, engineering, manufacturability and reliability

MicroElectroMechanical Systems (MEMS) technology offers considerable potential throughout the manufacturing sector, because of certain intrinsic advantages in terms of low cost, reliability, and small size. Relatively simple MEMS are used in applications ranging from automobile air bag sensors to electronic games. Considerably more complex devices have been designed for defense applications, for which government funding is available; however, the fledgling industry suffers from insufficient knowledge of materials physics at micrometer size and from the fact that currently commercialized MEMS devices are designed for specialized and rather disparate purposes, do not have a broad user base, and therefore have not generated industry standards or the design and process software that would be built upon those industry standards. In addition to industry standards, further advances in MEMS technology require a more complete understanding of the physics underlying performance and reliability. The first half of this paper reviews general issues related to fabrication and commercialization; the second half addresses the technical materials issues that relate to MEMS performance and reliability.