Acharya, S., Wang, X., Xu, Q., Zhang, M., Chai, J., Luo, P., Lim, P. C., Yang, P., Shen, L., Sun, C., & Yao, K. (2024). Role of oxygen on structure and piezoelectric properties of Al0.65Sc0.35N thin films. Physical Review Applied, 22(4). https://doi.org/10.1103/physrevapplied.22.044071
Abstract:
Al1-xScxN thin films have emerged as a technologically important material for several piezoelectric and ferroelectric device applications ranging from acoustic filters, and micro-electromechanical systems (MEMS), to memories. Such applications require materials to be grown with high structural quality and optimal properties. However, it is challenging to completely eliminate oxygen contamination, which is persistently present in Al1-xScxN thin films produced by sputtering deposition, particularly with increasing Sc content. In this study, we examine the role of oxygen on the structure and its effect on the piezoelectric and dielectric properties of Al0.65Sc0.35N thin film. Our theoretical analysis and experimental results suggested that depending on concentration oxygen can have contrasting effects on the piezoelectric properties of Al0.65Sc0.35N thin films. Oxygen concentration in the range of 1.2 at% to 4.3 at% severely degrades the structural coherence of the films, and consequently the piezoelectric coefficient from 10.5 to 8.2 pm/V. Electrical characterization and DFT calculations indicated the existence of defects of ON type and (3ON-VAl) type depending on oxygen concentration. Our DFT calculations further suggested that at low oxygen concentrations where the substitutional defect of ON is favored, the piezoelectric coefficient can be nearly 1.5 times higher compared to its counterpart without oxygen.
License type:
Publisher Copyright
Funding Info:
This research / project is supported by the A*STAR, - Advanced Manufacturing and Engineering (AME) Programmatic Fund
Grant Reference no. : A20G9b0135
Description:
The publisher source must be acknowledged with a citation. The publication can be found in 10.1103/PhysRevApplied.22.044071.