Surface acoustic wave propagation properties in AlN/3C-SiC/Si composite structure

Abstract

Highly c-axis oriented aluminum nitride (AlN) films were grown on epitaxial cubic silicon carbide (3C-SiC) layers on Si (100) substrates using alternating current (AC) reactive magnetron sputtering at temperatures between 300°C to 450°C. The AlN thin films were characterized by X-ray diffraction, scanning electron microscope, and transmission electron microscopy. Two-port surface acoustic wave (SAW) devices were fabricated on the AlN/3C-SiC/Si layered structure. The SAW propagation properties in the AlN/3C-SiC/Si layered structure were theoretically and experimentally investigated. The Rayleigh mode exhibited a high acoustic velocity of 5,200 m/s due to the epitaxial 3C-SiC layer. The results demonstrate the potential of AlN thin films grown on epitaxial 3C-SiC layers to create piezoelectric acoustic devices for frequency control and harsh environment applications.