[22a-P01-1~4] 6.1 Ferroelectric thin films

▲ [22a-P01-4] Polarity inversion of scandium aluminum nitride (ScAlN) piezoelectric thin films by using Ge addition

〇Sri Ayu Anggraini¹, Masato Uehara¹, Kenji Hirata¹, Hiroshi Yamada¹, Morito Akiyama¹ (1.AIST)

Keywords:Piezoelectric, polarity, ScAlN

Controlling the polarity of ScAlN-based thin films is expected encourage the development of more advanced broadband BAW filter that is suitable for higher frequency range in 5G communication technology. As a method to control the polarity, addition of silicon (Si) into AlN has been reported to inverse the polarization direction of non-doped aluminum nitride (AlN) from Al-polar to N-polar [1], which was also effective to control the polarity of ScAlN piezoelectric thin film [2]. Since Si and germanium (Ge) belong to the same group in the periodic table, we hypothesized that addition of Ge should be capable of inversing the polarization direction of ScAlN. For a non-doped AlN, addition of Ge has been confirmed to successfully inverse the polarity from Al-polar to N-polar [3]. Therefore, in this study we would like to investigate whether the use of Ge can also be used as a method to inverse the polarization direction of ScAlN.
References:
[1] S. A. Anggraini, M. Uehara, K. Hirata, H. Yamada, M. Akiyama, Scientific Reports (2020) 10, 4369.
[2]S. A. Anggraini, M. Uehara, K. Hirata, H. Yamada, M. Akiyama, JSAP Spring Meeting 2021.
[3] Mizuno, T. et al. In 2017 19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS). 1891.