Crystalline structure effect on the performance of flexible ZnO/polyimide surface acoustic wave devices

Abstract

This paper reports the fabrication of flexible surface acoustic wave (SAW) devices on ZnO/polyimide substrates and investigation of the effects of the deposition conditions, crystal quality, and film thickness of the ZnO films on the performance of the SAW devices. The deposition pressure has a significant effect on the crystal quality of the ZnO film, and which in turn affects the transmission of the SAW devices strongly. The device performance improves greatly and is mainly attributed to the better crystal quality of the film deposited at high pressure. The performance of the SAW devices also improves significantly with increase in ZnO film thickness, owing to the reduced defects and improved piezoelectric effect for the films with large grain sizes and better crystallinity as the film thickness increases. Flexible SAW devices with a resonant frequency of 153 MHz, a phase velocity of 1836 m/s, and a coupling coefficient of 0.79% were obtained on the ZnO film of 4 μm thickness, demonstrated its great potential for applications in electronics and microsystems.

Discrete microfluidics based on aluminum nitride surface acoustic wave devices

“…Furthermore, the bulk material cannot form devices for flexible electronic application. Conversely, piezoelectric thin films are compatible with IC processing and have the potential to be used for flexible lab-on-a-chip (Jin et al 2013;Zhou et al 2013b).…”

“…Experimental transmission (S 21 ) (in red) and reflection (S 11 ) (in blue) signals of a typical AlN SAW device Microfluid Nanofluid performance of the SAW resonator(Zhou et al 2013b;Chung and Phan 2010). The relationships among stress, strain, electric field and electric displacement field in the stress-charge of a piezoelectric crystal are given by the piezoelectric constructive as(Chung and Phan 2010):…”

Comparison of Deposition Methods of ZnO Thin Film on Flexible Substrate

“…ZnO indicate that the crystal quality becomes better with increasing the 0002 peak as mention by J. Zhou, et al, in [13]. As sol-gel give thicker ZnO thin film, the 0002 peak is higher then other methods.…”

AlScN thin film based surface acoustic wave devices with enhanced microfluidic performance

“…There are several methods that enable determining the Young's modulus and hardness of thin coatings based on nanoindentation tests. 25,[39][40][41][42][43] Among these, the extrapolation of measured elastic modulus and hardness values of the coated systems to zero contact depth based on ISO14577 standard is simple and effective 39 and this will be adopted in study here. As shown in Fig.…”