Crystallinity Dependence of Self-organized Process During Porous Anodization of Aluminum

Porous-type anodization is carried out on thin aluminum film deposited on silicon substrate by electron beam evaporation technique. TEM examination of the obtained alumina film shows a much more less ordered pore arrangement compared with those produced from bulk aluminum under long anodization period condition. This discrepancy in pore ordering degree can be caused by many factors such as anodization period, applied electrolyte and voltage.Furthermore, a newly introduced crystallinity should also be carefully taken into account. Due to the polycrystalline structure of the thin A1 film rather different from that nearly single crystalline of bulk Al, the inteffacial region of its Al grains, which induces some extent of fluctuation in atomic density and relative anodizing rate along the direction of the pore development in comparison with groins themselves, will give an effect to the self-organized process during anodization by disturbing the electric field distribution at the pore bottom.