Murata Manufacturing Co., Ltd.

Resonant, Inc.

Doug Jachowski

Bryant Garcia

Patrick J Turner

Neal O Fenzi

Robert B Hammond

Greg Dyer

Ryo Wakabayashi

Ventsislav Yantchev

An acoustic resonator is fabricated by bonding a first piezoelectric plate to a substrate and spans locations for a first and second cavity in the substrate. A top surface of the first piezoelectric plate is planarized to a first thickness. A bonding layer is formed on the first piezoelectric plate and spans the first and second cavity locations. A second piezoelectric plate is bonded to the bonding layer and spans the first and second cavity locations. A portion of the second piezoelectric plate spanning the second cavity location is etched away to form a first membrane over the first cavity location and a second membrane over the second cavity location. Interdigital transducers are formed on the first and second membranes over the first and second cavity location to form a first and second resonator on the same die.

Resonators with different membrane thicknesses on the same die

Band N77 bandpass filters include a first plurality of transversely-excited film bulk acoustic resonators (XBARs) on a first chip comprising a first rotated YX-cut lithium niobate piezoelectric plate having a thickness less than or equal to 535 nm, and a second plurality of XBARs on a second chip comprising a second rotated YX-cut lithium niobate piezoelectric plate having a thickness greater than or equal to 556 nm. A circuit card is coupled to the first chip and the second chip. The circuit card includes conductors for making electrical connections between the first chip and the second chip.

Split-ladder band N77 filter using transversely-excited film bulk acoustic resonators

Acoustic resonators are disclosed. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. The back surface is attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm spanning a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the piezoelectric plate. The IDT includes: a first busbar and a second busbar disposed on respective portions of the piezoelectric plate other than the diaphragm; a first set of elongate fingers extending from the first bus bar onto the diaphragm; and a second set of elongate fingers extending from the second bus bar onto the diaphragm, the second set of elongate fingers interleaved with the first set of elongate fingers.

Transversely-excited film bulk acoustic resonators with interdigital transducer configured to reduce diaphragm stress

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Santa Cruz, CA, United States of America

Doug Jachowski