Electrodeposited Nickel Nanodots Array on the Silicon Wafer

Nanoporous anodic aluminum oxide (AAO) membrane has many advantages as a host material for a variety of magnetic materials. The magnetic materials can be embedded into the host pores by electrodeposition, sputtering, and infiltration routes. This work shows that the entire fabrication process to the magnetic nanomaterial through the AAO templating method can be thoroughly integrated with silicon technology. Thin aluminum film is directly deposited on the titanium precoated silicon wafer by dc sputtering. Subsequent twostep anodization of the aluminum film results in uniform morphology of the long-range ordered array of cylindrical alumina nanopores, which is used as a template for the electrochemical growth of the Ni nanodots array. The observed magnetic hysteresis loops at 10 K and room temperature show unique ferromagnetic coupling for the Ni nanodot array depending on field directions.