Prevention of decomposition of phosphorous containing substrates during an epitaxial growth sequence

Abstract

Loss of phosphorous from a phosphorous containing substrate is eliminated by maintaining a partial pressure of phosphorous in the vicinity of the substrate higher than the inherent partial pressure of phosphorous over the material of the substrate. The higher phosphorous partial pressure is obtained by positioning in the vicinity of the substrate a solution of an element such as tin or antimony containing phosphorous. The solvent metals are so chosen as to have higher solubility for phosphorous compared to the solution of phosphorous in the substrate material. The solution is exposed to the substrate in close juxtaposition but does not make physical contact with the substrate. The phosphorous vapor pressure above the solution will be proportional to the concentration of phosphorous in the solution. Consequently, since the solution is selected to have a higher solubility for phosphorous compared to solutions consisting of substrate elements, the vapor pressure will be proportionally higher. Thus, the region above the exposed substrate will contain phosphorous at a vapor pressure higher than the inherent vapor pressure of the material of the substrate and phosphorous loss is eliminated.

Dependencies are inferred from the claim text.