Morphology-enhanced metal-alumina adhesion by depositing textured alumina films on textured Teflon substrates

Abstract

An enhanced adhesion between metals and alumina has been achieved by texturing the alumina films. The Al2O3 films are deposited on textured Teflon substrate; the latter was presputtered to provide a textured surface for the alumina deposition. For thin alumina layers of about 500-Å, a textured surface is obtained which is nearly identical to that of the starting Teflon. On such an alumina surface, an increase in peel strength of about 40-50 times is obtained for both Cu and Cu90%-Cr10%, from those deposited on nontextured alumina using nontextured Teflon substrates. With an increasing thickness of alumina, the height of the surface texture is reduced, resulting in less enhancements in peel strength than those on the 500-Å alumina. The results are in agreement with the model for the morphology-enhanced adhesion, which was proposed to explain the previously observed enhancement in adhesion between Cu and textured Teflon. The work also provides a simple way of generating a textured surface for the ceramic materials for an enhanced adhesion with metals needed for a variety of technologies.