Microstructural characterization at the interface of Al 2 O 3 /ZnO/Al 2 O 3 thin films grown by atomic layer deposition

In this study, the effects of the annealing temperature and time on Al 2 O 3 /ZnO/Al 2 O 3 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 30 s at 600, 620, and 700 °C in a N 2 atmosphere, and other samples were annealed for 30 s, 5 min, and 10 min at 700 °C. The decrease in the thickness of ZnO showed a parabolic tendency at these temperature and time ranges, and ZnAl 2 O 4 was formed by the reaction between ZnO and Al 2 O 3 at 620 °C. Although the generated ZnAl 2 O 4 grains could not have strict epitaxial relations with the ZnO grains, the stain in the ZnAl 2 O 4 grains was considerably influenced by the orientation relation between ZnO and ZnAl 2 O 4 which was related to the oxygen rearrangement for the ZnAl 2 O 4 generation.