In this regard, the two- and three-dimensional AFM images (1 lm 1 lm) of HfO2 multilayer structures
are shown in Figs. 1–3 respectively for samples A1, A2 and A3. These micrographs reveal that
films do not show continuous long trenches or blotches, which are indicative of a crack free and pinhole-
free surfacee surface under investigation.