A study was reported of the vapor-phase diffusion of Al into single crystals of n-type (111) float-zone material. The resultant diffusion profiles were measured by using resistivity techniques. No specific diffusion data were presented, but qualitative observations were described. Thus, diffusion temperatures greater than 1150C yielded lower surface concentrations. This was partly due to an increase in Al vapor oxidation. At lower pressures and lower diffusion temperatures, the partial pressure increased to the extent that the surface concentration in the Si corresponded to the solid solubility of the impurity. Under these conditions, the surface concentration was independent of the Al vapor pressure and was reproducible and uniform; even if the vapor pressure was not.

S.Azimi-Nam: Journal of Materials Science Letters, 1987, 6[9], 1073-5