The Dielectric Loss of Wurtzite Al<inf>1-X</inf>Sc<inf>x</inf>N Thin Films for Mass Production of Piezoelectric MEMS

The enhancement of the electromechanical coupling coefficient caused by Sc substitution in AlN-based piezoelectric MEMS devices can be exploited successfully only if the dielectric losses remain confined to low values. While the magnitude of the piezoelectric activity in Al _1-x Sc _x N thin films has been described widely in the literature, the impact of the Sc content on the loss tangent has not been studied extensively. In this work we discuss the dissipation factor obtained for x=0.095 and x=0.3 on Mo and Pt bottom electrodes, for full capacitor stacks deposited with an EVATEC Clusterline ^® 200-II PVD tool equipped with single alloy targets 304mm in diameter.