Voids in Anodic Aluminum Oxide Films

Abstract

films were examined by transmission electron microscopy using defocus contrast. Phase contrast effects have been observed in both amorphous and crystalline anodic films. These contrast effects have been interpreted as arising from discrete voids, 2–4 nm in diameter, present at apparent densities in the range . Strings of connected phase objects were seen in crystalline oxide and these may be the cross section of cracks that are thought responsible for the electrical instability of these films. No phase objects were detected in several anodic films that were examined.