Fabrication of Free-Standing Nanoscale Alumina Membranes with Controllable Pore Aspect Ratios

Abstract

Porous alumina films with controllable pore sizes and having submicrometer film thicknesses were fabricated by the anodization of Al overlayers. The Al was deposited by sputtering onto either glass or onto silicon that had been coated with a layer of silicon nitride. Alumina membranes having thicknesses between 300 and 1000 nm were prepared analogously using a lithographic process to produce free-standing porous alumina films that were peripherally supported on a 500-μm-thick silicon substrate.