Surface acoustic wave devices on AlN/3C–SiC/Si multilayer structures

Abstract

Surface acoustic wave (SAW) propagation characteristics in a multilayer structure including a piezoelectric aluminum nitride (AlN) thin film and an epitaxial cubic silicon carbide (3C-SiC) layer on a silicon (Si) substrate are investigated by theoretical calculation in this work. Alternating current (ac) reactive magnetron sputtering was used to deposit highly c-axis-oriented AlN thin films, showing the full width at half maximum (FWHM) of the rocking curve of 1.36 • on epitaxial 3C-SiC layers on Si substrates. In addition, conventional two-port SAW devices were fabricated on the AlN/3C-SiC/Si multilayer structure and SAW propagation properties in the multilayer structure were experimentally investigated. The surface wave in the AlN/3C-SiC/Si multilayer structure exhibits a phase velocity of 5528 m s −1 and an electromechanical coupling coefficient of 0.42%. The results demonstrate the potential of AlN thin films grown on epitaxial 3C-SiC layers to create layered SAW devices with higher phase velocities and larger electromechanical coupling coefficients than SAW devices on an AlN/Si multilayer structure. Moreover, the FWHM values of rocking curves of the AlN thin film and 3C-SiC layer remained constant after annealing for 500 h at 540 • C in air atmosphere. Accordingly, the layered SAW devices based on AlN thin films and 3C-SiC layers are applicable to timing and sensing applications in harsh environments.

SAW Characteristics of AlN/SiO2/3C-SiC Layered Structure With Embedded Electrodes

“…As for the substrate, cubic silicon carbide (3C-SiC) becomes a more attractive candidate since it offers not only a high V (~13,000 m/s) but also a little piezoelectricity when compared to commonly used fast substrates such as diamond and sapphire, etc. Chih-Ming Lin et al [4] theoretically and experimentally demonstrated that the SAW in AlN/3C-SiC/Si multilayer structure with top interdigital transducer (IDT) electrodes exhibits a high V of 5,528 m/s and large K 2 of 0.42% for the fundamental mode while a very small K 2 for the second mode.…”

“…However, the main drawback of such layered structure is that the patterned IDT electrodes harms AlN crystalline growth and causes cracks due to the edge discontinuities of the electrodes [4], [9]. The defects limit both device performance and reliability.…”

Magnetron Sputtered AlN Layers on LTCC Multilayer and Silicon Substrates

“…To employ the pyro-and piezoelectric properties in microelectromechanical and electronic devices, c-axis oriented AlN is required [8,9]. The same holds also for acousto-electronic devices [10,11], nonlinear optics and optomechanical devices, [12] as well as phononic crystals [13].…”

Full-Wave Analysis of Ultrahigh Electromechanical Coupling Surface Acoustic Wave Propagating Properties in a Relaxor Based Ferroelectric Single Crystal/Cubic Silicon Carbide Layered Structure

“…3C-SiC is an attractive candidate substrate given its high velocity and 2 [15,16]. This paper reports a full-wave analysis of YX-PIMNT/3C-SiC substrate conducted via the finite-element method (FEM) with the commercial software package COMSOL Multiphysics.…”