The availability of new piezoelectric materials compatible with silicon chip integration for micro-electromechanical systems (MEMS) application is a highly attractive prospect. These new materials will help to bridge the gap between mechanical and electronic devices, making MEMS increasingly small and efficient. AlN is today’s industry’s standard and research is intensifying worldwide on AlN derivatives such as ScAlN. By alloying AlN with Sc, the crystal lattice is locally distorted due to the phase competition between the rock-salt ScN and wurtzite AlN structures, resulting in a progressive transition of AlN from wurtzite into a hexagonal-layered structure as the amount of Sc dopant atoms increases. This, in turn, induces an enhancement of the piezoelectric coefficients of ScAlN up to 50% Sc content (see figure).
One of our research interests is to apply different computational techniques to discover new piezoelectric materials with enhanced piezoelectric coefficients. We have started with the exhaustive characterization of ScAlN, already published. After a break in this front, we are looking forward to starting a new international collaboration in 2020, including industry partners, on discovery of new piezoelectric materials (details to follow).