The effect of surface nitridation upon Sn diffusion at 1100C was investigated. The nitridation, which was associated with vacancy generation, was found to enhance Sn diffusion. This was suggested to occur because the large Sn atoms preferred to diffuse via vacancies. On the basis of published values of the vacancy supersaturation which was generated by the nitridation of bare Si, it was estimated that 33% of the Sn diffused via vacancies. However, the actual percentage might be higher because the high Sn concentration could affect nitridation-induced vacancy generation. The effect of oxidation was unclear.

B.P.R.Marioton, U.Gösele: Japanese Journal of Applied Physics, 1989, 28[7], 1274-5