A INTRODUCTION

There are two fundamental native defects in silicon the lattice vacancy and the silicon interstitial. Each is present in thermodynamic equilibrium at any finite temperature T, its concentration being proportional to exp(-W/kT), where W is its formation energy. At elevated temperatures, therefore, each provides a mechanism for normal thermally activated diffusion of the substitutional host and impurity atoms. In addition, non-equilibrium conditions produced during device processing such as oxidation, annealing of plasma etching, ion implantation damage, etc., can serve to provide a temporary release of these defects, which, in turn, can cause anomalous transient enhanced diffusion phenomena.

In addition, these defects, whether isolated or complexed with other defects or impurities, represent a disruption of the normal bonding structure of the lattice, and therefore can introduce electrically active levels into the forbidden gap. They therefore directly affect the electrical properties of the material. This also means that the defects can take on several charge states, each potentially with a different structural arrangement in the lattice, different diffusional properties, different interactions with other defects, etc. Determining, therefore, their electronic and physical properties, and the relationship of these to their local structural arrangements in the lattice, is essential to understanding their role in silicon device technology.

In this Datareview, we will summarize briefly what is presently believed to be established concerning the isolated intrinsic defects and their interactions with impurities in silicon...