Formation and Composition of Surface Layers and Solubility Limits of Phosphorus During Diffusion in Silicon

A neutron activation analysis was used to study the behavior of phosphorus during its diffusion into silicon and silicon dioxide films. Certain correlations were found between the compositions of the oxide layers formed during the diffusions and the existing phase diagram of the system . In several experiments the concentration of phosphorus in silicon had reached the solubility limit, and a layer with very high phosphorus content was found to be present between the oxide film and the silicon substrate.