Experimental Characterization of ZnO Thins Films and Identification of Frequency Peaks in ZnO/SiO₂/Si SAW Devices

摘要

In this work, we investigate experimentally the different properties of ZnO thins films deposited by radio-frequency magnetron with Zinc target (sputtering method) and we calculate the frequency peaks in ZnO/SiO₂/Si structure. We study the effect of the power and the pressure deposition on the thin films properties. We characterized by X-ray diffraction the film crystalline quality and by scanning electron microscopy (SEM) the film morphology. The X-ray diffraction analyses has revealed that the ZnO film is polycrystalline in nature having a hexagonal wurtzite type crystal structure and (002) orientation. The SEM showed that the structure of the films is columnar. The thickness of the films is measured by profilometer apparatus (Dektak³ ST). The principal application of ZnO thin films is the SAW (surface acoustic wave) devices. We realized experimentally the ZnO/SiO₂/Si structure with the optimal parameters. The frequency response of the device is measured by the network analyzer. We obtained the frequency of 476 MHz for a phase velocity of 5712 ms-¹.