Electron Microscope Observations of the Crystallization of Anodically Formed Tantalum and Niobium Oxide Films

Abstract

Anodic oxide films ranging in thickness from about 200 to 1000Aå were formed on electropolished surfaces of tantalum and niobium by conventional techniques. The films were then stripped from the metal, given a variety of thermal treatments in vacuum, and examined directly in the electron microscope. Crystallization of the amorphous films was induced by high‐temperature annealing or in the microscope itself by increasing the beam intensity. The distinguishing features of each type of crystallization process are discussed and illustrated with appropriate micrographs.