Impact of SAW device passivation on RF performance

Author

Marks, B.W. ; Sheddrick, D.W. ; Shen Jen

Author_Institution

RF Monolithics, Dallas, TX, USA

Volume

1

fYear

1999

fDate

17-20 Oct. 1999

Firstpage

1

Abstract

Passivation layers consisting of sputtered Al₂O₃ have been deposited onto SAW devices for the purpose of reducing the incidence of shorts. A coupling-of-modes model was used with one-port resonators, coupled resonator filters and test structures. The passivation layer stiffens the surface, with a velocity increase proportional to (t/λ), where t is the passivation layer thickness. Attenuation is increased slightly, producing a 0.25 dB increase in the loss of a one-port resonator at 314 MHz. The effect on reflectivity is minimal, and of much lesser importance to the designer.

Keywords

alumina; passivation; radiofrequency filters; sputtered coatings; surface acoustic wave resonator filters; surface acoustic wave resonators; 314 MHz; Al₂O₃; Al₂O₃ sputtered layer; RF characteristics; SAW device; coupled resonator filters; coupling-of-modes model; one-port resonator; passivation; test structure; Attenuation; Insertion loss; Passivation; Radio frequency; Reflectivity; Resonator filters; Surface acoustic wave devices; Surface acoustic waves; Testing; Transducers;

fLanguage

English

Publisher

ieee

Conference_Titel

Ultrasonics Symposium, 1999. Proceedings. 1999 IEEE

Conference_Location

Caesars Tahoe, NV

ISSN

1051-0117

Print_ISBN

0-7803-5722-1

Type

conf

DOI

10.1109/ULTSYM.1999.849344

Filename

849344