Bulk acoustic wave/film bulk acoustic wave resonator and filter for wide bandwidth applications

A ladder filter comprising:

• an input port and an output port;
• a plurality of series arm bulk acoustic wave resonators electrically connected in series between the input port and the output port;
• and
• a plurality of shunt bulk acoustic wave resonators connected in parallel, each of the shunt bulk acoustic wave resonators being electrically connected between respective adjacent ones of the plurality of series arm bulk acoustic wave resonators and ground, each of the plurality of series arm bulk acoustic wave resonators and the plurality of shunt bulk acoustic wave resonators including a film of piezoelectric material, an upper electrode disposed on top of the film of piezoelectric material, and a layer of dielectric material disposed on top of the upper electrode in each of a central active region, a recessed frame region, and a raised frame region the layer of dielectric material being thinner in the recessed frame region than in the central region and thicker in the raised frame region than in the recessed frame region, the central active region being surrounded by the recessed frame region and the raised frame region surrounding the recessed frame region in each respective resonator of the plurality of series arm bulk acoustic wave resonators and the plurality of shunt bulk acoustic wave resonators, a combined thickness of the upper electrode and layer of dielectric material being greater in the central active region of each respective resonator than in the recessed frame region, the combined thickness of the upper electrode and layer of dielectric material being greater in the raised frame region than in the central active region, at least one of the plurality of shunt bulk acoustic wave resonators including a raised frame region having a first width, and at least one of the plurality of series arm bulk acoustic wave resonators including a raised frame region having a second width less than the first width.

An electronics module comprising a radio frequency ladder filter including:

• a plurality of series arm film bulk acoustic wave resonators electrically connected in series between an input port and an output port of the ladder filter;
• and
• a plurality of shunt film bulk acoustic wave resonators electrically connected in parallel between adjacent ones of the plurality of series arm film bulk acoustic wave resonators and ground, each of the plurality of series arm bulk acoustic wave resonators and the plurality of shunt bulk acoustic wave resonators including a film of piezoelectric material, an upper electrode disposed on top of the film of piezoelectric material, and a layer of dielectric material disposed on top of the upper electrode in each of a central active region, a recessed frame region, and a raised frame region, the layer of dielectric material being thinner in the recessed frame region than in the central region and thicker in the raised frame region than in the recessed frame region, the central active region being surrounded by the recessed frame region and the raised frame region surrounding the recessed frame region in each respective resonator of the plurality of series arm bulk acoustic wave resonators and the plurality of shunt bulk acoustic wave resonators, a combined thickness of the upper electrode and layer of dielectric material being greater in the central active region of each respective resonator than in the recessed frame region, at least one of the plurality of shunt film bulk acoustic wave resonators including a raised frame region including the film of piezoelectric material, the upper electrode disposed on top of the film of piezoelectric material, and the layer of dielectric material disposed on top of the upper electrode surrounding the recessed frame region and having a first width, the combined thickness of the upper electrode and layer of dielectric material being greater in the raised frame region than in the central active region, at least one of the plurality of series arm film bulk acoustic wave resonators having a raised frame region having a second width less than the first width.

An electronic device comprising an electronics module including a radio frequency ladder filter having:

• a plurality of series arm film bulk acoustic wave resonators electrically connected in series between an input port and an output port of the ladder filter;
• and
• a plurality of shunt film bulk acoustic wave resonators electrically connected in parallel between adjacent ones of the plurality of series arm film bulk acoustic wave resonators and ground, each of the plurality of series arm bulk acoustic wave resonators and the plurality of shunt bulk acoustic wave resonators including a film of piezoelectric material, an upper electrode disposed on top of the film of piezoelectric material, and a layer of dielectric material disposed on top of the upper electrode in each of a central active region and a recessed frame region, the central active region being surrounded by the recessed frame region in each respective resonator of the plurality of series arm bulk acoustic wave resonators and the plurality of shunt bulk acoustic wave resonators, a combined thickness of the upper electrode and layer of dielectric material being greater in the central active region of each respective resonator than in the recessed frame region, at least one of the plurality of shunt film bulk acoustic wave resonators including a raised frame region including the film of piezoelectric material, the upper electrode disposed on top of the film of piezoelectric material, and the layer of dielectric material disposed on top of the upper electrode surrounding the recessed frame region and having a first width, the combined thickness of the upper electrode and layer of dielectric material being greater in the raised frame region than in the central active region, the layer of dielectric material being thinner in the recessed frame region than in the central region and thicker in the raised frame region than in the recessed frame region, at least one of the plurality of series arm film bulk acoustic wave resonators having one of a raised frame region having a second width less than the first width or lacking any raised frame region.