Method for fabricating film bulk acoustic resonator (FBAR), FBAR, and filter

A FBAR, comprising:

• a substrate;
• a dielectric material layer formed on a surface of the substrate away from the substrate;
• a bottom electrode formed on a surface of the dielectric material layer away from the substrate;
• a piezoelectric material layer formed on the substrate;
• an intermediate metal layer formed on a surface of the piezoelectric material layer away from the substrate;
• a mass load layer formed on a surface of the intermediate metal layer away from the substrate;
• and
• a top electrode formed on a surface of the mass load layer away from the substrate;
• a final mass load layer formed by dry etching the top electrode;
• wherein the intermediate metal layer is configured to protect the piezoelectric material layer from being affected in operations of forming the mass load layer on the surface of the intermediate metal layer away from the substrate, and forming the top electrode on the mass load layer.

A filter comprising a first FBAR group and a second FBAR group, wherein the first FBAR group is a combination of at least two FBARs formed on a same substrate and connected in series with a predetermined circuit, the second FBAR group is a combination of at least two FBARs connected in parallel with another predetermined circuit;

• wherein each of the at least two FBARs in the first FBAR group and the at least two FBARs in the second FBAR group comprises:
• a substrate;
• a dielectric material layer formed on a surface of the substrate away from the substrate;
• a bottom electrode formed on a surface of the dielectric material layer away from the substrate;
• a piezoelectric material layer formed on the substrate;
• an intermediate metal layer formed on a surface of the piezoelectric material layer away from the substrate;
• a mass load layer formed on a surface of the intermediate metal layer away from the substrate;
• and
• a top electrode formed on a surface of the mass load layer away from the substrate;
• a final mass load layer formed by dry etching the top electrode;
• wherein the intermediate metal layer is configured to protect the piezoelectric material layer from being affected in operations of forming the mass load layer on the surface of the intermediate metal layer away from the substrate, and forming the top electrode on the mass load layer.