Patent ID: 6515558
Filing Date: 2003-02-04
Classification: H03H

Abstract:
A method for fabricating a filter including a thin film bulk acoustic wave resonator (FBAR), the FBAR having a plurality of layers of different materials deposited on top of each other and on top of a substrate, the FBAR including a piezolayer sandwiched between a top electrode on the side of the piezolayer facing away from the substrate, and a bottom electrode on the side of the piezolayer facing the substrate, the FBAR also including an acoustic mirror situated closer to the substrate with a lowest layer in contact with the substrate over the entire surface of the lowest layer facing the substrate, the method characterized by a step of selecting from only among low acoustic impedance materials one or more materials from which to form the bottom electrode, and a step of forming the bottom electrode only from the one or more materials so selected, thereby increasing the power handling capacity of the filter.