DIFFUSION OF S-35 INTO SILICON USING AN ELEMENTAL VAPOR SOURCE

Diffusion of S into Si was investigated by the closed ampoule technique using the radioactive tracer S-35. Erfc-type penetration profiles determined by mechanical sectioning originated from exposure of the samples to evaporated elemental sulfur. Diffusion coefficients in the temperature range 1328-1671 K obey the Arrhenius law with an activation energy of 1.80 eV and a pre-exponential factor of 4.7 x 10(-6) M2 S-1. This high diffusivity can be reconciled with the preferred incorporation of S on lattice sites by invoking substitutional-interstitial exchange. Within this concept the measured long-range transport appears to be controlled by a minority of interstitial S atoms.