Ferroelectrics, microsystems and nanotechnology

Abstract

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 etc) in which there is a dimension of less than 100nm which is critical to performance or behaviour. It covers a wide range of activities from ultra-precision engineering and fine-line lithography through nanostructured materials to the manipulation of biological molecules. There is a strong overlap with the subject of microsystems technology (MST), whereby systems incorporating sensing, signal processing, actuation and communications are integrated into a single microengineered package. Ferroelectric materials offer a wide range of properties which can be used in microsystems and nanotechnology, 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 could lie in the fields of nanoscale fabrication and information storage. The potential for ferroelectric thin films to contribute to these fields is discussed, and problems reviewed, especially from the aspect of materials and process integration. Specific examples of the factors critical to the growth and behaviour of thin films at low temperature by sol gel are discussed.

Keywords:

• ferroelectric
• microsystems
• nanotechnology
• ferroelectric thin films
• PZT
• sol-gel