MEMS Design & Optimisation
Microelectromechanical systems (MEMS) consist of micron scale components which interact with their surrounding environment as sensors, actuators or both. Classic examples of consumer MEMS devices include accelerometers, micromirrors and microphones. The technology continues to advance with gravity sensing and biomedical devices emerging. Relative to macro scale systems, their large surface area to volume ratios increase the importance of electromagnetic and fluid dynamic effects. A multiphysics approach is therefore fundamental to the design of MEMS devices for which Xi have a proven experience across physical domains and orders of scale.
The fabrication process for MEMS devices emerged from semiconductor techniques where thin layer deposition, photolithographic patterning and etch steps define the geometry. By selectively patterning and etching sacrificial layers it is possible to release mechanical structures which can form the basis of a transducer. An understanding of how the process flow affects structural topology and device behaviour can be critical to the manufacturability of a device. MEMS devices demand a fully-coupled multiphysics approach for simulation with the sensitivity of mechanical structures to viscous damping and electrostatic spring softening being two common examples.
Xi’s engineers are experienced with the design and optimisation of MEMS transducers based on modern foundry processes. COMSOL Multiphysics is our principal modelling tool which provides the ability to solve across physical domains including structural mechanics, acoustic, fluid dynamics and electromagnetics. The use of shell or membrane elements to compute thin film mechanics, contact simulations for stress or stiction recovery analysis and fully-coupled electro-mechanics for pull-in and resonance extraction are some examples of MEMS concerns that Xi have extensive experience with.