High concentration antimony diffusion into silicon using auxiliary wafers

The behavior of auxiliary wafers used for Sb diffusion has been studied, with the auxiliary wafers set face to face with diffusion wafers. A high Sb concentration, as high as the solid solubility of Sb into silicon, was attained by auxiliary wafers lapped with alumina powder but not attained by those lapped with carborundum powder. Sapphire substrates, chemical vapor deposition-Al2O3 film deposited on silicon wafers, and Al+ -implanted silicon wafers were used for the auxiliary wafers, and they brought desirable results. Chemical analysis showed that the glass layer grown on the diffusion wafer contained aluminum oxide, which was estimated to give a high Sb concentration in the diffusion wafer.