The Piezoelectricity of AlScN Thin Films under High-Pressure Regime

Abstract

This study investigated the structural, mechanical, piezoelectric, and electromechanical properties of AlScN thin films using density functional theory (DFT) under varying levels of applied pressure, ranging from 0 to 20 GPa. The primary focus of this research is to explore the feasibility of optimizing AlScN thin films for surface acoustic wave (SAW) applications through pressure-induced modifications. Our findings reveal two significant outcomes. First, we observe a notable increase in the elastic constant C₃₃ as a function of pressure. This increase signifies a substantial enhancement in material stiffness, directly influencing wave propagation and velocity within the thin films. Second, a remarkable 68% improvement in the piezoelectric constant, d₃₃, is identified for Al_0.75Sc_0.25N at an applied pressure of 20 GPa compared to Al_0.75Sc_0.25N at 0 GPa. This enhancement has a profound impact on the electromechanical coupling characteristics of the material. These results underscore the potential for tuning the piezoelectric response of AlScN thin films using applied pressure, offering a promising avenue for enhancing the performance of SAW-based AlScN devices.