Microstructural characterization at the interface of Al2O3/ZnO/Al2O3 thin films grown by atomic layer deposition

Abstract

In this study, the effects of the annealing temperature and time on Al2O3/ZnO/Al2O3 thin films grown by the atomic layer deposition (ALD) method were examined using transmission electron microscopy (TEM) and energy dispersion spectroscopy (EDS). Samples were annealed for 30s at 600, 620, and 700 degrees C in a N-2 atmosphere, and other samples were annealed for 30s, 5 min, and 10 min at 700 degrees C. The decrease in the thickness of ZnO showed a parabolic tendency at these temperature and time ranges, and ZnAl2O4 was formed by the reaction between ZnO and Al2O3 at 620 degrees C. Although the generated ZnAl2O4 grains could not have strict epitaxial relations with the ZnO grains, the stain in the ZnAl2O4 grains was considerably influenced by the orientation relation between ZnO and ZnAl2O4 which was related to the oxygen rearrangement for the ZnAl2O4 generation.