Point Defects, Diffusion Mechanisms, and the Shrinkage and Growth of Extended Defects in Silicon

Abstract

ABSTRACTThe paper introduces the basic point-defect models proposed for silicon, which involve either vacancies or self-interstitials only, or both types of point defects simultaneously under thermal-equilibrium conditions. The growth and shrinkage kinetics of oxidation-induced stacking faults as well as oxidation-enhanced or -retarded diffusion phenomena are discussed within the frame work of these models. Whereas no unambiguous conclusions on the dominant diffusion mechanism can be drawn from the available oxidation-related experiments, recent investigations on so-called anomalous diffusion phenomena (e.g., the ‘emitter-push effect’) and on the diffusion of gold in silicon demonstrate Si self-interstitials to be the point defects governing self- and impurity diffusion. The possibility of a coexistence of vacancies and self-interstitials in thermal equilibrium is discussed in this context. The paper concludes with speculations on how carbon in conjunction with self-interstitials may influence the nucleation process of oxygen precipitates in silicon.