Theory of The Oxidation of Metals and Semiconductors: The Phenomenon of Isoparametric Generation of Nonstoichiometric Point Defects in Anodic Oxide Films

Abstract

A unified theory of the oxidation of materials is formulated, according to which the differences between these processes are related to the degree of deviation from equilibrium of the processes of the generation and recombination of point defects at the boundary of the oxide film, which are responsible for mass transfer. Anodic oxidation occurs under nonequilibrium conditions and is controlled by the rate of generation of two types of basic point defects. The generation of both defects is characterized by the identity of parameters, and occurs as a result of a jump of the same particle (oxygen ion or metal) at the boundary of the oxide film, and this explains the phenomenon of simultaneous mobility of anions and cations. The mechanisms of isoparametric generation of a pair of point defects are proposed: the initiating jump mechanism and the displacement mechanism. Their implementation in oxides with excess or deficiency of oxygen is shown. Criteria are proposed for determining the mechanism of generation of defects during the oxidation of various substances. The conditions of thermal oxidation are close to equilibrium, and point defects have time to recombine at the oxide boundary; therefore, defects with a higher recombination activation energy predominate.