Improved Dielectric Properties for Anodic Aluminum Oxide Films by Soft/Hard Two‐Step Electrolytic Anodization

Abstract

A two‐step electrolytic anodization process, denoted as the "soft/hard" process, has been studied as a means of fabricating a high quality dielectric. A layer of porous (soft) anodized aluminum followed by boric acid barrier (hard) anodization produced a dense amorphous aluminum oxide with excellent dielectric properties. Effective dielectric constants of up to 19, bulk resistivities of up to 1018 Ω‐cm, and breakdown voltages up to twice that of the hard anodization forming voltage were observed.