Effects of Diffusion‐Induced Strain and Dislocation on Phosphorus Diffusion into Silicon

Abstract

The diffusion-induced strain and dislocation effects on the diffusion of phosphorus into silicon have been investigated. When phosphorus is diffused singly, the diffusion coefficient of phosphorus increases considerably at high concentrations. While, when phosphorus and germanium are diffused simultaneously, fewer dislocations are observed and the diffusion-induced strain is compensated. In strain-compensated diffusion, concentration profiles of phosphorus agree well with the theoretical curves (erfc). It is shown that the enhancement of the diffusion coefficient of phosphorus at high concentrations is attributed to the diffusion-induced strain. Besides, dislocations retard the diffusion front by absorbing excess vacancies, showing the opposite effect of strain.,Effects of diffusion-induced dislocations on diffusion of impurities into silicon have been studied extensively by many investigators. They have reported that diffusion of phosphorus above a certain critical surface concentration or a total amount of dopant