Study of roughness evolution and layer stacking faults in short-period atomic layer deposited HfO_2/AI_2O_3 multilayers

摘要

In this work we study the evolution of roughness in interfaces of HfO_2/Al_2O_3 multilayers by x-ray reflectivity. It was found that, besides the reduced adatom surface mobility during atomic layer deposition, an improvement of the interface quality can be achieved upon the stacking of several layers. Although the low roughness of the initial surface could not be recovered, there was a considerable improvement of surface/interface quality along the deposition process. In particular, variations on the growth temperature were not able to tailor the surface quality, if compared to the stacking process. Finally, transmission electron microscopy analysis has shown that local defects can take place among nearly perfect interfaces. Such effect must be taken into account for nanometer-scale device fabrication.