Dopant diffusion in silicon and polysilicon using phosphorus oxychloride (pocl_3)

摘要

A simple one-dimensional diffusion analysis of phosphorus in the silicon substrate, treated as a semi-infinite medium, predicts the depth profiles accurately. The prediction of phosphorus concentration in a silicon substrate requires a reasonably accurate value for the diffusion coefficient. Optimum values of the diffusion coefficient of phosphorus in silicon were obtained based on an inverse procedure that uses a minimization principle. The emphasis is on understanding the dopant diffusion in the silicon substrate and polysilicon films. Two substrates were used for this study, bare silicon and polysilicon. All the polysilicon wafers had an underlying oxide layer. The values of the diffusion coefficient for phosphorus in silicon agree well with those reported in the literature, however, they are within a much narrower error band.