17.2.4 Future Developments – Nanotechnology and MEMS

Flextensional actuator - source University
of Pennsylvania

Thin film technology is seen as the way to reduce the size and cost of most ceramic applications, producing finer lines and greater circuit density. The whole new development area of nanotechnology is very relevant to thin film electroceramic technology, as it has the potential to achieve devices with sub-micron dimensions. For example, thin film ceramics are key to the development of Micro Electro Mechanical Systems (MEMS) that have opened up a whole new potential area for electronic ceramics. Furthermore multi-layer ceramics allow easy inclusion of MEMS devices. MEMS are made up of electronic and mechanical components, including ceramic microsensors and microactuators using semiconductor integrated circuit processing technology. Thin film piezoelectric ceramics can provide a direct mechanical to electrical (and vice-versa) coupling to a MEMS device, interfacing directly with the silicon cantilevers and membranes, or forming the active device themselves. Such a device is the previous 2 GHz acoustic wave filter.

MEMS can result in better quality circuits and devices, together with lower cost and lower power consumption. Zinc oxide was the first ceramic used in MEMS, but along with PZT, aluminium nitride is now used. The first application was for pressure sensors then accelerometers. Because of their improved performance over existing devices they rapidly took over the vehicle air-bag accelerometer market, while the largest market today is for ink jet print heads. These two applications each had markets well in excess of $200 million by 2009, when the overall MEMS global market was estimated to be some $7 billion. Other applications are digital micromirrors for deflecting lasers, motion sensors, acoustic/ultrasound devices, micromotors and micropumps. Potential future applications are limitless. For example, workers at Imperial College are developing a gunshot alert system using MEMS microphones embedded in headgear. Medical applications include ultrasonic transducers, microsurgical instruments and cochlear implants to improve hearing.

Example of cantilever and diagram
of final stage of cantilever
fabrication - source Sandia
and courtesy Waterloo University

Micro mechanical examples, micro motor and
micro generator - sources Scienceprog and
MEMGEN Corporation

Collection of MEMS devices - sources
Palomar Technologies, Fadikhalil.perso,
MIT and Electronic Design