Diamond‐SAW devices: a reverse fabrication method

Abstract

Surface acoustic wave (SAW) devices are key components in modern wireless communication systems. Besides being used as reflective delay lines, filters or resonators, SAW devices can be used as sensors and fixed‐code identification tags. Due to their high‐acoustic velo‐city, diamond films can be combined with piezoelectric materials to fabricate diamond‐based SAW devices with potential for high frequency applications. This paper presents results of coating commercial SAW delay lines with diamond films. The films were deposited on lithium niobate under different conditions in a hot filament chemical vapour deposition system. Seeding was performed using 6‐12 μm diamond grit and 20‐30 nm nano‐diamond particles based suspensions. After tuning the deposition conditions, dies of 74 MHz delay lines were coated with diamond. The quality, morphology and conformability of the coatings were evaluated by scanning electron microscopy (SEM) and Raman spectroscopy. The integrity of the interdigitated transducers (IDTs) after deposition was evaluated by SEM. S‐parameters of as‐bought and diamond‐coated dies were measured using a network analyser. Although the frequency response is attenuated after diamond deposition, integrity of the IDTs and the operating principle of the devices are kept intact. These preliminary results open the door to a simplified fabrication procedure of diamond‐based SAW devices. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Measuring bulk and surface acoustic modes in diamond by angle-resolved Brillouin spectroscopy

“…Diamond shows excellent performance in the high-frequency and high-power acoustic wave devices, thanks to its superhigh elastic modulus and thermal conductivity, stable chemical property as well as low thermal expansion coefficient and dielectric constant [10] . The piezoelectric film/diamond multilayer structure has been extensively applied in high-frequency and high-power SAW devices [11][12][13] . In addition, the emergent quantum acoustodynamics (QAD) cavities based on diamond make a contribution for the development of the hybrid quantum devices [14,15] .…”

Giant Reflection Coefficient on Sc0.26Al0.74N Polycrystalline Diamond Surface Acoustic Wave Resonators

“…There have been several fabrication routes proposed for diamond‐based SAWs: piezoelectric thin films on the nucleation surface of the diamond substrate (this work), embedding the interdigital transducers (IDTs) by either depositing the piezoelectric thin film on the nucleation surface of as‐grown diamond substrates or coating the IDT and piezoelectric thin film with a diamond layer grown by chemical vapor deposition (CVD) …”