Defects Induced by Deep Diffusion of Phosphorus into Silicon

Abstract

Defects induced by diffusion of phosphorus in silicon have been found to develop to considerable distances beyond the diffusion front. The extension of dislocations into silicon has been found to depend on the surface treatment before diffusion. The X-ray diffraction topography has been used to study the structures and distribution of the lattice imperfections. When phosphorus is diffused in dislocation free silicon crystals, separated dislocation loops and precipitates as well as the ordinary dislocations are observed. Dislocation loops consist of hexagonal loops and disc shaped ones which have 1/3 <111> type Burgers vectors. The precipitate has an elastic strain with circular symmetry and may be considered to be phosphorus or phosphorus rich silicon. The mechanisms of the generation of these defects are briefly discussed.