Temperature-compensated film bulk acoustic resonator above 2 GHz

Author

Pang, Wei ; Yu, Hongyu ; Zhang, Hao ; Kim, Eun Sok

Author_Institution

Dept. of Electr. Eng.-Electrophys., Univ. of Southern California, Los Angeles, CA, USA

Volume

26

Issue

6

fYear

2005

fDate

6/1/2005 12:00:00 AM

Firstpage

369

Lastpage

371

Abstract

Two different types of temperature-compensated film bulk acoustic resonators (FBARs) are designed, fabricated, and tested. One is formed by integrating FBAR with a surface-micromachined air-gap capacitor, which passively reduces the FBAR´s temperature coefficient of frequency (TCF) by about 40 ppm/°C at 2.8 GHz. With this approach, zero TCF would easily have been achieved if the FBARs were built on AlN rather than ZnO. The other type of temperature compensated FBAR is built on a surface-micromachined SiO₂ cantilever that is released by XeF₂ vapor etching of silicon. The Al-ZnO-Al-SiO₂ FBAR is measured to have a TCF of -0.45 ppm/°C (between 85°C and 110°C) at 4.4 GHz.

Keywords

acoustic resonators; aluminium; bulk acoustic wave devices; etching; micromachining; microwave devices; silicon compounds; xenon compounds; zinc compounds; 2.8 GHz; 4.4 GHz; Al-ZnO-Al-SiO₂; FBAR temperature coefficient of frequency; Si; XeF₂; air-gap capacitor; film bulk acoustic resonators; surface-micromachining; temperature compensation; vapor etching; Air gaps; Capacitors; Composite materials; Fabrication; Film bulk acoustic resonators; Radio frequency; Resonant frequency; Temperature; Young´s modulus; Zinc oxide; Air-gap capacitor; film bulk acoustic resonators (FBARs); surface micromaching; temperature compensation;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/LED.2005.848113

Filename

1432902