Metal layer thickness influence on the dispersion characteristics of SH-waves in the structures “Me/ZnO/Me/diamond” and “Me/AlN/Me/diamond”

The research paper presents the results of computer simulation of the influence of mass loading represented by two metal layers on variations in the phase velocity of the dispersion shear modes of the elastic wave in the piezoelectric layered structures Me/ZnO/Me/diamond and Me/AlN/Me/diamond depending on the frequency and the ratio of the metal layer thickness to the piezoelectric crystalline layer thickness. The materials of the piezoelectric layers and the substrate have a set of such significant properties as the large values of the electromechanical coupling coefficient for piezoelectric and the significant values of the phase velocities for bulk waves and surface acoustic wave in diamond. Aluminum (Al), molybdenum (Mo) and platinum (Pt) are considered as the metal layer materials, which are most often used in the manufacturing of acoustoelectronic devices. It was found that variation in the elastic wave phase velocity depends on the acoustic impedance of metal layer and its thickness. More significant changes in Δv/v values at low acoustic impedance values of the metal layer occur due to a change in the thickness of the lower electrode. However, if the acoustic impedance of the metal layer is comparable with the acoustic impedance of the substrate, the increase in Δv/v values is largely due to the thickness of the upper metal layer. The results of the simulation can be used in the development of various acoustoelectronic devices, including components of the electronic base of rocket and space technology.