Surface acoustic wave (SAW) devices based on an aluminum nitride (AlN)/diamond layered structure are attractive due to their high operating frequency. To enhance the operating frequency of a diamond SAW device, we demonstrated one piezoelectric layer on diamond by doping AlN with boron. In this study, highly c-axis-oriented wurtzite boron-aluminum nitride (B, Al)N films were deposited on diamond by a co-sputtering technique. The resulting films exhibit a higher piezoelectric coefficient d 33 and higher Young's modulus than AlN films. Moreover, the greater rigidity of (B, Al)N film further boosts the resonance frequency of a diamond SAW device. Considering the SAW wavelength (λ = 2 μm), the calculated surface acoustic velocities (V S) of (B, Al)N on diamond is 8860 m/s that is higher than AlN on diamond (8720 m/s). We also find that the electromechanical coupling coefficient (K 2) of a SAW device based on (B, Al)N on diamond was the same (∼ 0.5%) as that of one based on AlN on diamond.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Metals and Alloys
- Materials Chemistry