[16p-P07-1~5] 9.1 Dielectrics, ferroelectrics

▲ [16p-P07-4] Controlling the polarity of scandium aluminum nitride (ScAlN) piezoelectric thin film via Si addition

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

Keywords:ScAlN, piezoelectric, polarity

Scandium aluminum nitride (ScAlN) has been touted as a future material for many promising electronic applications including the radio frequency (RF) resonators, owing to its excellent piezoelectricity, high acoustic velocity and high k²factor [1-2]. Since the non-centrosymmetry of wurtzite structure is the origin of polarization along c-axis, a highly c-oriented ScAlN piezoelectric thin film could exhibits either aluminum/scandium (Al/Sc) or nitrogen (N) polarity. A thin film either having Al/Sc- or N-polarity could lead to thin films with different electronic properties and eventually affect the performance of the developed devices. For example, having a stack of N-polar layer on top of an Al-polar layer could improve the performance of a solidly mounted resonator BAW (SMR-BAW) compared with that using a single layer Al-polar thin film [3]. Thus, controlling the polarity of ScAlN-based thin films is expected to enable the development of broadband BAW filter that is suitable for 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 [4]. Therefore, in this study, we propose the use of Si as dopants to control the polarity of ScAlN piezoelectric thin film.
References:
[1] M. Akiyama, T. Kamohara, K. Kano, A. Teshigashara, Y. Takeuchi, N. Kawahara, Adv. Mater. (2009) 21, 593.
[2] M. Moreira, T. Torndahl, I. Katardajiev, T. Kubart, J. Vac. Sci. Technol. A 33(2015) 021518.
[3] Mizuno, T. et al. In 2017 19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS). 1891.
[4] S. A. Anggraini, M. Uehara, K. Hirata, H. Yamada, M. Akiyama, Scientific Reports (2020) 10, 4369.