Avago Technologies International Sales Pte. Limited

Alexia Kekoa

David Martin

Lovell Harold Camnitz

Domingo Figueredo

Sean T Hansen

Hans G Rohdin

Kun Wang

Brice Ivira

Bernhard Ulrich Koelle

Keri Liane Williams

Lori Ann Callaghan

Bulk acoustic wave (BAW) resonators, and electrical filters that incorporate the BAW resonators, are described. Generally, the BAW resonators comprise a substrate comprising an acoustic reflector; a first electrode disposed over the acoustic reflector; a piezoelectric layer disposed over the first electrode, the piezoelectric layer comprising scandium-doped aluminum nitride (ASN); a diffusion barrier layer disposed over the piezoelectric layer; and a second electrode disposed over the diffusion barrier layer. The diffusion barrier layer configured to prevent diffusion of material of the first electrode into the piezoelectric layer.

Bulk acoustic wave resonators having doped piezoelectric material and an adhesion and diffusion barrier layer

In a bulk acoustic resonator device, at least one additional metal feature is formed on a top surface of the bottom electrode at a location at which the bottom electrode electrical contact will subsequently be formed, thereby thickening the metal at the location below where the piezoelectric material layer will be etched to form the opening for the bottom electrode electrical contact. Consequently, even though some of the metal of the additional metal feature and/or of the bottom electrode will be removed during the process of etching the opening in the piezoelectric material layer, the bottom electrode will always retain sufficient thickness after the piezoelectric material layer is etched.

Bulk acoustic resonator devices and processes for fabricating bulk acoustic resonator devices

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Alexia Kekoa