Nucleation and growth of stacking faults in epitaxial silicon during thermal oxidation

Abstract

An optical and electron microscopy study of the nucleation and growth of stacking faults in {001}-oriented epitaxial silicon has been carried out following pretreatment of the crystal in hydrofluoric acid and thermal oxidation in steam at 1050°C. A direct correlation of the etched surface structure as revealed by interference contrast optical and scanning electron microscopy with substructural defects as revealed by transmission electron microscopy has been established for times ≥1 min. The observations are divided into five stages which, taking the TEM observations as a reference, are (i) formation of a needle-shaped precipitate at the Si–SiO2 interface; (ii) nucleation of an interfacial Frank dislocation; (iii) climb of the Frank dislocation into the silicon substrate; (iv) formation of an equilibrium-shaped stacking fault; and (v) stacking-fault interactions.