Wide bandgap semiconductor thin films for piezoelectric and piezoresistive MEMS sensors applied at high temperatures: an overview

The use of wide bandgap semiconductor thin films as sensing materials for micro-electrical-mechanical systems (MEMS) sensors has been the subject of much discussion in the academic and industrial communities. The motivation is that such materials are recognized as being suitable for extreme environment applications, namely: high temperatures, intense radiation and corrosive atmospheres. Among the wide bandgap semiconductor materials, aluminum nitride (AlN), zinc oxide (ZnO), diamond-like carbon (DLC) and silicon carbide (SiC) are highlighted due to their inherent sensing properties and compatibility with MEMS fabrication processes. Here we show an overview on the development technologies and applications of AlN, ZnO, DLC and SiC thin films in piezoelectric and piezoresistive MEMS sensors. Emphasis is placed on the influence of the temperature on the piezoelectric and piezoresistive properties of these films.