Newly Developed High Q FBAR with Mesa-Shaped Membrane

Abstract

In this paper, we present the newly developed high Q Film Bulk Acoustic Resonator (FBAR) which has the piezoelectric AlN film sandwiched between two electrode films and mesa-shaped membrane structure by utilizing poly-Si and XeF2 as a sacrificial layer and dry release gas, respectively. By controlling the etching profile of bottom electrode and sacrificial layer, the poor formation of AlN in the edge region of mesa-shaped membrane could be eliminated. In addition, by reducing the parasitic overlap which both of the electrodes and the piezoelectric layer resides directly on the substrate, we could improve the characteristics of resonator and filter. When we compare with the typical surface micro-