Copyright © 1977 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

To compare the properties of anodized aluminium oxide layers an easy thickness determination method is wanted. Crevecoeur and De Wit used a method expressing the thickness in terms of peak voltages obtained by forming again after annealing. The aim of the work described here is to relate the value of the peak voltage to the thickness of the layer measured by ellipsometry.

On specimens formed in an aqueous solution of b oric acid and ammonium hydroxide the following relation is found between the thickness d (nm) and peak voltage Vp (volt):d = 1.020 Vp + (0.00044 ± 0.00011) Vp2. On specimens formed in a solution of ammonium pentaborate in ethylene glycol the squared Vp term is of a lower value. however when Vp is less than 150 V the above relation holds for layers formed in both electrolytes, the systematic error then being less than 1%.