[17p-PB01-1~4] 9.1 Dielectrics, ferroelectrics

▲ [17p-PB01-4] Effect of addition of elements in group IVB (C, Si, Ge, Sn) on polarity inversion of Scandium Aluminum Nitride (ScAlN) piezoelectric thin films

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

Keywords:Piezoelectric, ScAlN, Polarity

The outstanding piezoelectricity of scandium aluminum nitride (ScAlN) has successfully brought improvement to the performance of radio frequency (RF) filter for wireless communication [1,2]. With the arrival of 5G communication era, the RF filter is required to work at much higher frequency and wider bandwidth to allow larger data transfer. One way to improve the performance of a RF filter is by employing multilayers of piezoelectric thin films with different polarities, for example the use of Al-polar AlN/N-polar germanium aluminum nitride (GeAlN) has enabled a solidly mounted resonator BAW (SMR-BAW) to function at much higher frequency [3]. Based on those findings, the utilization of a stack of Al-polar and N-polar ScAlN-based thin film is expected to enhance the performance of RF filter compared with that using one layer of ScAlN with single polarity. Thus, controlling the polarity of ScAlN piezoelectric thin film is paramount for the development of next generation RF filter. As a method to control the polarity, addition of element such as silicon (Si) or germanium (Ge) into AlN has been reported to successfully inverse the polarization direction of aluminum nitride (AlN) [3,4] as well as ScAlN [5,6]. Since Si and germanium (Ge) belong to the group IVB in the periodic table, we investigated the effect of addition of each element in group IVB (carbon (C), Si, Ge, tin (Sn)) on the polarity of ScAlN thin films.
References:
[1] M. Akiyama et al, Adv. Mater. (2009) 21, 593.
[2] M. Moreira et al, Vacuum, (2011) 86, 23.
[3] Mizuno, T. et al. 2017 19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS). 1891.
[4] S. A. Anggraini et al, Scientific Reports (2020) 10, 4369.
[5] S. A. Anggraini et al, JSAP Spring Meeting 2021.
[6] S. A. Anggraini et al, JSAP Fall Meeting 2021.