[9p-E311-1~21] CS.7 Code-sharing session of 6.1 & 15.4

6:30 PM - 6:45 PM JST(9:30 AM - 9:45 AM UTC)

[9p-E311-20] Exploration of Area-Selective Control Method of Spontaneous Polarization Direction of AlN Thin Film for PMUT Application

〇Shinsuke Ukita¹, Akihiko Teshigahara¹, Shinya Yoshida¹ (1.Shibaura Univ.)

Keywords:

Aluminum nitride,Polarization Direction,piezoelectric Micromachined Ultrasonic Transducer (pMUT)

To achieve a push-pull driven pMUT using a single-phase power supply, this study investigated the spontaneous polarization inversion phenomenon of AlN thin films depending on the presence or absence of a native oxide layer on a Si substrate. The AlN film continuously deposited after removing the native oxide via reverse sputtering exhibited an opposite polarity of d₃₃ (-6.5 pC/N) compared to that on the untreated substrate (+7.0 pC/N). Furthermore, it was confirmed that the native oxide layer was gradually reformed with increasing atmospheric exposure time, and the crystal inversion completely disappeared after 24 hours. These results demonstrate the feasibility of a domain-selective polarization control technology.