Use of fluorine-doped silicon oxide for temperature compensation of radio frequency surface acoustic wave devices

Satoru Matsuda, Motoaki Hara, Michio Miura, Takashi Matsuda, Masanori Ueda, Yoshio Satoh, Ken Ya Hashimoto

    Research output: Contribution to journalArticlepeer-review

    14 Citations (Scopus)

    Abstract

    This paper investigates acoustic properties, including the temperature coefficient of elasticity (TCE), of fluorine-doped silicon oxide (SiOF) films and proposes the application of the films to the temperature compensation of RF SAW devices. From Fourier transform infrared spectroscopy (FT-IR), SiOF films were expected to possess good TCE properties. We fabricated a series of SAW devices using the SiOF-overlay/Cu-grating/LiNbO 3-substrate structure, and evaluated their performance. The experiments showed that the temperature coefficient of frequency (TCF) increases with the fluorine content r, as we expected from the FT-IR measurement. This means that the Si-O-Si atomic structure measurable by the FT-IR governs the TCE behavior of SiO 2-based films even when the dopant is added. In comparison with pure SiO 2 with the film thickness h of 0.3 wavelengths (λ), TCF was improved by 7.7 ppm/°C without deterioration of the effective electromechanical coupling factor K 2 when r = 3.8 atomic % and h = 0.28λ. Fluorine inclusion did not obviously influence the resonators' Q factors when r < 8.8 atomic %.

    Original languageEnglish
    Article number6138735
    Pages (from-to)135-138
    Number of pages4
    JournalIEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
    Volume59
    Issue number1
    DOIs
    Publication statusPublished - 2012 Jan

    ASJC Scopus subject areas

    • Instrumentation
    • Acoustics and Ultrasonics
    • Electrical and Electronic Engineering

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