Impact of SAW device passivation on RF performance

Author

Marks, Burton W. ; Sheddrick, Don W. ; Jen, Shen

Author_Institution

RF Monolithics, Dallas, TX, USA

Volume

48

Issue

5

fYear

2001

Firstpage

1362

Lastpage

1366

Abstract

Passivation layers consisting of sputtered Al/sub 2/O/sub 3/ 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 (CRF), and test structures. The passivation layer stiffens the surface with a velocity increase proportional to t//spl lambda/, 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

UHF filters; passivation; surface acoustic wave resonator filters; surface acoustic wave resonators; 314 MHz; Al/sub 2/O/sub 3/; Al/sub 2/O/sub 3/ sputtered film; RF characteristics; SAW device passivation; coupled resonator filter; coupling-of-modes model; one-port resonator; patterned layer; test structure; Aluminum oxide; Attenuation; Electrodes; Insertion loss; Passivation; Radio frequency; Reflectivity; Surface acoustic wave devices; Testing; Transducers;

fLanguage

English

Journal_Title

Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on

Publisher

ieee

ISSN

0885-3010

Type

jour

DOI

10.1109/58.949745

Filename

949745