Fabrication of in situ ultrathin anodic aluminum oxide layers for nanostructuring on silicon substrate

The authors demonstrate a method for the fabrication of in situ ultrathin porous anodic aluminum oxide layers (aspect $ratio<2:1$⁠) on Si, which can be directly used as templates for nanodot preparation and for pattern transfer. The regular shape of the aluminum oxide pores is maintained even when the thickness of the aluminum oxide template is reduced to $50nm$⁠. By using these in situ ultrathin templates as lift-off masks, the authors successfully prepared a $BaxSr1−xTiO3$ nanodot array on Si surface. Furthermore, these nanotemplates are employed as lithographic masks to transfer the nanopattern into the silicon substrate.