Monolithic FBAR duplexer and method of making the same

US6407649B1 · kind B1 · utility

Assignee

• Nokia · FI

Inventors

• Pasi Tikka · Munich, DE
• Juha Ellä · Halikko, FI
• Jyrki Kaitila · Riemerling, DE

Key dates

• Filing date: Jan 5, 2001
• Grant date: Jun 18, 2002
• Expiry date: Jan 5, 2021

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T29/42
• WIPO field: Basic communication processes
• WIPO sector: Electrical engineering

Abstract

A monolithic bulk acoustic wave (BAW) duplexer, and a method for fabricating same, the duplexer having a, transmitter section as a first component filter and a receiver section as a second component filter, both component filters fabricated on a single substrate and both including at least one shunt BAW resonator and one series BAW resonator, each BAW resonator including a resonator section atop an isolation structure provided so as to separate the resonator section from the substrate, including: a patterned bottom electrode material for use as the bottom electrode of each of the resonators of the duplexer; a patterned piezoelectric material for use as the piezolayer of each of the resonators of the duplexer; a patterned top electrode material for use as the top electrode of each of the resonators of the duplexer; a tuning layer for the shunt resonator of each of the two component duplexer filters; and a tuning layer for both the series and shunt resonators of one of the two component duplexer filters. In some applications, each isolation structure is an acoustic mirror. Also in some applications, the duplexer further includes at least one planar spiral inductor provided in the cou…