Surface-Acoustic-Wave Devices Based on Lithium Niobate and Amorphous Silicon Thin Films on a Silicon Substrate

Yansong Yang, Liuqing Gao, Songbin Gong

Research output: Contribution to journalArticlepeer-review

Abstract

This work presents an acoustic platform using solidly mounted thin-oriented lithium niobate (LiNbO3) film on silicon (Si). A thin layer of amorphous Si eliminates a conductive layer generated in the thin-film bonding processes and contributes to acoustic energy confinement and thermal frequency stability. The gigahertz operating frequency is achieved by resorting to the guided acoustic wave shear-horizontal wave (SH0) in a 400-nm-thick X-cut LiNbO3 thin film. Due to the elimination of the parasitic surface conduction (PSC) effect, the electromechanical coupling of the guide acoustic wave is maximized in the Si-based heterogeneous wafer. Due to the minimized acoustic impedance mismatch between surface material and substrate, longitudinal and higher order spurious modes are suppressed. Due to the stiff substrate with a small temperature expansion coefficient (TEC), the solidly mounted structure features a reduced temperature coefficient of frequency (TCF) and improved power handling. The fabricated resonator shows an extracted electromechanical coupling coefficient of 22.8%, a high loaded Q of 1208 at 1.6 GHz, and a TCF of -36 p/min/K. The compressed filter is demonstrated with a minimum insertion loss (IL) of 0.6 dB, a fractional bandwidth (FBW) of 8%, an out-of-band rejection of 30 dB, a TCF of -38.5 p/min/K at roll-off, and a miniaturized footprint of 0.4 mm2. The performance has shown the strong potential of the LiNbO3-Si platform for front-end applications in 5G.

Original languageEnglish (US)
Pages (from-to)5185-5194
Number of pages10
JournalIEEE Transactions on Microwave Theory and Techniques
Volume70
Issue number11
DOIs
StatePublished - Nov 1 2022
Externally publishedYes

Keywords

  • 5G wireless communications
  • Acoustic resonators
  • guided acoustic waves
  • lithium niobate (LiNbO-)
  • microelectromechanical systems (MEMS)
  • microwave acoustics
  • parasitic surface conduction (PSC)

ASJC Scopus subject areas

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

Fingerprint

Dive into the research topics of 'Surface-Acoustic-Wave Devices Based on Lithium Niobate and Amorphous Silicon Thin Films on a Silicon Substrate'. Together they form a unique fingerprint.

Cite this