The P diffusion gettering of Au is a reversible process which exhibits marked temperature and P concentration dependences. The Au concentration profile after successful gettering followed the P profile, but almost all of the Au atoms were found in regions where the P concentration exceeded about 3 x 1019/cm3. This was attributed to a large enhancement of Au solubility which occurred when the P concentration was greater than 3 x 1019/cm3. The simplest explanation for the observed gettering was the assumed formation of Au-P pairs within the highly-doped P layer. However, quantitative agreement could not be obtained between the present results and a simple segregation model. If the Au bulk solubility was modified by taking account of a supersaturation of Si self-interstitials, agreement between the model and the experimental data was then obtained.

E.O.Sveinbjörnsson, O.Engström, U.Södervall: Journal of Applied Physics, 1993, 73[11], 7311-21