Ferroelectrics, microsystems and nanotechnology

The term "Nanotechnology" was first coined by Taniguchi in 1974 to describe the precision manufacture of mechanical parts with finishes and tolerances in the nanometer range. However, the term has now expanded in its meaning to cover the fabrication and exploitation of entities (materials, devices e tc) in which there is a dimension of less than 100nm which is critical to p erformance or behaviour. It covers a wide range of activities from ultra-pr ecision engineering and fine-line lithography through nanostructured materi als to the manipulation of biological molecules. There is a strong overlap with the subject of microsystems technology (MST), whereby systems incorpor ating sensing, signal processing, actuation and communications are integrat ed into a single microengineered package. Ferroelectric materials offer a w ide range of properties which can be used in microsystems and nanotechnolog y, particularly the pyroelectric effect for thermal infra-red detection and imaging and the piezoelectric effect for sensors (sound, acceleration etc) , and for actuators (e.g. cantilevers and motors). Ultimate applications co uld lie in the fields of nanoscale fabrication and information storage. The potential for ferroelectric thin films to contribute to these fields is di scussed, and problems reviewed, especially from the aspect of materials and process integration. Specific examples of the factors critical to the grow th and behaviour of thin films at low temperature by sol gel are discussed.