Dominant Factor for the Concentration of Phosphorus Introduced by Vapor Phase Doping (VPD)

Abstract

The dominant factor for the surface concentration of n-type impurity, introduced by vapor phase doping technique using phosphine, was investigated and the possibility of a high surface concentration was pursued. It was found that the surface concentration of phosphorus could be controlled dominantly by the PH3 partial pressure. It was confirmed that the phosphorus atoms adsorb on the surface of the silicon substrate throughout the doping process. A new diffusion model via the adsorption layer at the surface is proposed. Electrically active phosphorus with a surface concentration as high as 8×1019 atoms/cm3 was successfully obtained.