About MEMS
The field of MEMS evolved as engineers and scientists explored new avenues to make use of the fabrication technologies developed by the microelectronics industry. These technologies enabled complex micron and submicron structures to be integrated with electronic systems and batch fabricated at low cost. Mechanical devices fabricated using these technologies have become known as
microelectromechanical systems
(MEMS) or alternatively as microsystems. A proper description of these devices usually requires multiple physical effects to be incorporated.
At the microscale, different physical effects become important to those dominant at macroscopic scales. Inertial forces, which scale with the volume of the system, become comparatively less important than effects that scale more favorably when the system size is reduced, such as electrostatic forces. Consequently electrostatically actuated devices have been developed to measure acceleration and rotation with high accuracy in a small package. These accelerometers and gyroscopes have found widespread application in the automotive industry (where they are used to deploy airbags), in industrial applications (as sensors), and in consumer applications (where smartphones have driven rapid growth in the use of MEMS devices in recent years). Capacitive sensing has also led to widespread adoption of capacitive pressure sensors, which have largely superseded the piezoresistive pressure sensors that were some of the first MEMS devices to come to market. Piezoelectric MEMS devices have also become common with the widespread adoption of FBAR (thin–film bulk acoustic resonator) technology in mobile communication applications. Although there are few commercially important devices that employ thermal actuation (largely due to the high power consumption of such devices), thermal phenomena, such as packaging-induced thermal stresses, are often important in the design of MEMS devices. Finally, for resonant MEMS devices such as accelerometers, damping phenomena are important and there is a need for detailed modeling of phenomena such as thin-film damping. Very high quality factor resonators are often used in MEMS timing applications, and for these devices the quality factor can be limited by thermoelasticity: the intrinsic coupling of the thermal and structural domains that exists as a result of the laws of thermodynamics.
Microfluidic systems are often included within the field of MEMS and represent a growing market for MEMS devices. For modeling microfluidics devices, the dedicated Microfluidics Module contains tailored physics interfaces for the simulation of microfluidic devices, including creeping flow, multiphase flow, electrokinetic effects, and slip flow.