High-frequency lamb wave device composed of MEMS structure using LiNbO 3 thin film and air gap

Michio Kadota, Takashi Ogami, Kansho Yamamoto, Hikari Tochishita, Yasuhiro Negoro

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

High-frequency devices operating at 3 GHz or higher are required, for instance, for future 4th generation mobile phone systems in Japan. Using a substrate with a high acoustic velocity is one method to realize a high-frequency acoustic or elastic device. A Lamb wave has a high velocity when the substrate thickness is thin. To realize a high-frequency device operating at 3 GHz or higher using a Lamb wave, a very thin (less than 0.5 m thick) single-crystal plate must be used. It is difficult to fabricate such a very thin single crystal plate. The authors have attempted to use a c-axis orientated epitaxial LiNbO3 thin film deposited by a chemical vapor deposition system (CVD) instead of using a thin LiNbO3 single crystal plate. Lamb wave resonators composed of a interdigital transducer (IDT)/the LiNbO3 film/air gap/base substrate structure like micro-electromechanical system (MEMS) transducers were fabricated. These resonators have shown a high frequency of 4.5 and 6.3 GHz, which correspond to very high acoustic velocities of 14 000 and 12 500 m/s, respectively, have excellent characteristics such as a ratio of resonant and antiresonant impedance of 52 and 38 dB and a wide band of 7.2% and 3.7%, respectively, and do not have spurious responses caused by the 0th modes of shear horizontal (SH0) and symmetric (S0) modes.

Original languageEnglish
Article number5611703
Pages (from-to)2564-2571
Number of pages8
JournalIEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Volume57
Issue number11
DOIs
Publication statusPublished - 2010 Nov 1

ASJC Scopus subject areas

  • Instrumentation
  • Acoustics and Ultrasonics
  • Electrical and Electronic Engineering

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