Characterization of electron beam evaporated ZnO thin films and stacking ZnO fabricated by e-beam evaporation and rf magnetron sputtering for the realization of resonators

High quality Zinc oxide thin films have been fabricated by reactive e-beam evaporation in an oxygen environment. The effect of air annealing on the optical and structural properties of the e-beam evaporated ZnO is investigated. Raman spectroscopy has been found to be an efficient tool to evaluate the residual stress in the as-grown ZnO films from the position of the E2 (high) mode. Photoluminescence and transmittance measurements showed that the best optical and structural quality of the e-beam evaporated ZnO occurred at 300 °C. Finally, thin films of ZnO evaporated by e-beam technique have served to eliminate the compressive stress due to the sputtered piezoelectric ZnO and therefore to improve the quality of the fabricated resonators by stacking these ZnO layers fabricated by electron beam technique and rf magnetron sputtering, respectively.