Generation and Distribution of Dislocations by Solute Diffusion

Abstract

The stress introduced by solute lattice contraction of boron and phosphorus in silicon is shown to be sufficient to generate dislocations in silicon wafers. Such dislocations were observed. Expressions for the density distribution and for the total number of dislocations generated are derived and a mechanism of dislocation generation and distribution during the diffusion process is postulated. The dislocation distribution is shown to be highly dependent upon the nature of the diffusion process, expressions being derived for the conditions of (1) constant surface concentration of solute and (2) diffusion from a finite source. An expression for and means to determine the residual stresses in diffused silicon wafers are given.