Gold-Induced Dislocation Loops in Silicon Crystals

Abstract

The nature of dislocation loops formed by the diffusion of gold into crucible-grown and dislocation-free silicon crystals has been studied in some detail by X-ray diffraction topography and optical microscope. Four types of loops are observed. It is found that faulted loops with stacking fault are mast frequently formed. The faulted loop is considered to be a Frank sessile interstitial loop. Generation of the loop is found to be closely related to the distribution of pre-existing oxygen atoms, the concentration of the doped impurity and the grown-in dislocation density in the sample. It is concluded that the loop source is associated with oxygen precipitate, and the loop is believed to be formed by a process analogous to the Bardeen-Herring mechanism.