Enhanced Diffusion of Phosphorus due to BPSG layer in SEG-MOSFETs

We report on the enhanced diffusion characteristics of phosphorus in SEG(selective epitaxial growth)-MOSFETs due to in-diffusion from BPSG (borophosphosilicate glass) layer. Because of structural complexity of SEGMOSFETs, three-dimensional simulation was implemented and our results successfully show that a great deal of impurity in-diffusion from BPSG to silicon layer generates a lot of interstitial. Therefore, the diffusivity of phosphorus is increased dramatically by TED effect, causing the characteristics of SEGMOSFETs is degraded severely.