Wave propagation direction and c-Axis tilt angle influence on the performance of ScAlN/Sapphire-based saw devices

Abhay Kochhar, Yasuo Yamamoto, Akihiko Teshigahara, Ken Ya Hashimoto, Shuji Tanaka, Masayoshi Esashi

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


Some previously reported surface acoustic wave (SAW) devices using bulk piezoelectric substrates showed higher acoustic power radiated in either forward or backward wave propagation direction depending on their crystal orientations and are called natural single-phase unidirectional transducers (NSPUDT). While these reports were based on bulk piezoelectric substrates, we report directionality in the c-axis tilted 44% scandium doped aluminum nitride thin piezoelectric film-based SAW devices on sapphire. It is worth noting that our observance of directionality is specifically in Sezawa mode. We produced a c-axis tilt up to 5.5° over the single wafer and examined the directionality by comparing the forward and backward insertion loss utilizing split finger electrodes as a receiver. The wave propagation direction and c-axis tilt angle influence on the performance of SAW devices is evaluated. Furthermore, return loss and insertion loss data are presented for various SAW propagation directions and c-axis tilt angles. Finally, the comparison for both acoustic modes, i.e., Rayleigh and Sezawa, is reported.

Original languageEnglish
Article number7432042
Pages (from-to)953-960
Number of pages8
JournalIEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Issue number7
Publication statusPublished - 2016 Jul


  • Sc-doped aluminum nitride thin film
  • c-axis tilt
  • natural single-phase unidirectional transducers (NSPUDT)
  • radio frequency
  • surface acoustic wave (SAW) devices

ASJC Scopus subject areas

  • Instrumentation
  • Acoustics and Ultrasonics
  • Electrical and Electronic Engineering


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