Characterization of the surface acoustic wave devices based on ZnO/nanocrystalline diamond structures

Autor: Xiao Tao Zu, Luis Garcia-Gancedo, Frank Placido, Yong Qing Fu, William I. Milne, Y.W. Gu, Samuele Porro, Jikui Luo, Hua-Feng Pang, Andrew J. Flewitt, John I. B. Wilson
Rok vydání: 2013
Předmět:
Zdroj: physica status solidi (a). 210:1575-1583
ISSN: 1862-6300
DOI: 10.1002/pssa.201228631
Popis: Nanocrystalline ZnO films with strong (0002) texture and fine grains were deposited onto ultra-nanocrystalline diamond (UNCD) layers on silicon using high target utilization sputtering technology. The unique characteristic of this sputtering technique allows room temperature growth of smooth ZnO films with a low roughness and low stress at high growth rates. Surface acoustic wave (SAW) devices were fabricated on ZnO/UNCD structure and exhibited good transmission signals with a low insertion loss and a strong side-lobe suppression for the Rayleigh mode SAW. Based on the optimization of the layered structure of the SAW device, a good performance with a coupling coefficient of 5.2% has been realized, promising for improving the microfluidic efficiency in droplet transportation comparing with that of the ZnO/Si SAW device. An optimized temperature coefficient of frequency of −23.4 ppm °C−1 was obtained for the SAW devices with the 2.72 µm-thick ZnO and 1.1 µm-thick UNCD film. Significant thermal effect due to the acoustic heating has been redcued which is related to the temperature stability of the ZnO/UNCD SAW device.
Databáze: OpenAIRE