Surface acoustic wave characteristics of a ZnO/quartz substrate structure having a large electromechanical coupling factor and a small temperature coefficient

Michio Kadota

Research output: Contribution to journalArticle

64 Citations (Scopus)

Abstract

A substrate having a suitable electromechanical coupling factor (ks) value and a good temperature coefficient of frequency (TCF) is required for an applications of resonator surface acoustic wave (SAW) filters and rudder-type SAW filters requiring a specific bandwidth, because their bandwidth largely depends on the coupling factor of the substrate. Although a quartz substrate for SAW devices provides a good TCF, the electromechanical coupling factor obtained is small. The author speculated that an excellent TCF and an appropriate electromechanical coupling factor could be realized by combination of a quartz substrate having a positive TCF and a ZnO film having a negative TCF. As a result of theoretical and experimental investigations performed using a 29°45′ rotated Y and a 42°45′ rotated Y 35°X propagating quartz substrate, an excellent TCF (≈ 0 ppm/°C) and an appropriate coupling factor (ks = 0.1-0.11; ks2 = 0.01-0.0121) were realized with a zero degree power flow angle on the structure of IDT/ZnO/quartz or IDT/ZnO/shorted-plane/quartz for the first time.

Original languageEnglish
Pages (from-to)3076-3080
Number of pages5
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume36
Issue number5 SUPPL. B
DOIs
Publication statusPublished - 1997 May

Keywords

  • Coupling factor
  • Quartz
  • SAW
  • TCF
  • ZnO

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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