Investigation of material constants of CaTiO3 doped (K,Na)NbO3 film by MEMS-based test Elements

Ryosuke Kaneko, Michio Kadota, Yuji Ohashi, Jun ichi Kushibiki, Shinsuke Ikeuchi, Shuji Tanaka

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


A CaTiO3-doped (K,Na)NbO3 (KNN-CT) film is a lead-free piezoelectric film that is expected to substitute Pb(Zr,Ti)O3 (PZT) film in piezoelectric micro electro mechanical systems (MEMS). However, the full set of the material constants (elastic constants, piezoelectric constants and dielectric constants) of the KNN-CT film have not been reported yet. In this study, all the material constants of a sputter-deposited blanket KNN-CT film were investigated by the resonance responses of MEMS-based piezoelectric resonators and the phase velocities of leaky Lamb waves on a self-suspended membrane. The phase velocities measured by a line-focus-beam ultrasonic material characterization (LFB-UMC) system at different frequencies were fitted with theoretical ones, which were calculated from the material constants, including fitting parameters. A genetic algorithm was used to find the best-fitting parameters. All the material constants were then calculated. Although some problems arising from the film quality and the nature of deliquescence are observed, all the material constants were obtained exhibiting accuracy within 16 m/s in the phase velocity of leaky Lamb wave.

Original languageEnglish
Article number558
Issue number11
Publication statusPublished - 2018 Oct 29


  • Genetic algorithm
  • KNN-CT film
  • Leaky Lamb wave
  • Material constants
  • Piezoelectric resonance


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