Enhanced piezoelectric properties of c-axis textured aluminium scandium nitride thin films with high scandium content: Influence of intrinsic stress and sputtering parameters

Aluminium scandium nitride (ASN) exhibits a largely enhanced piezoelectric response as compared to aluminium nitride (AlN), which makes it an upcoming piezoelectric material for next generation RF filters, sensors, actuators and energy harvesting devices. In this work, process-microstructure-property relationships of such ASN films containing up to 40 at% Sc were investigated. Hereby, the influence of the process parameters on the film structure, the intrinsic stress and the piezoelectric response was carefully investigated.