The implantation of As into polycrystalline samples and drive-in diffusion into substrates was investigated by back-scattering analysis and electrical measurements. It was found that the effective diffusivity of implanted As in the polycrystalline material (table 5) could be described by:

D(cm2/s) = 6.3 x 10-1exp[-3.22(eV)/kT]

It was independent of the As concentration. The drive-in diffusion of As from the implanted layer was markedly affected by the atmosphere. In a N atmosphere, a considerable amount of As diffused outwards to the ambient. The out-diffusion could be suppressed by encapsulation with Si3N4. In an oxidizing atmosphere, As atoms were driven inwards by growing SiO2 due to segregation between SiO2 and Si. As a result, the drive-in diffusion of As was enhanced.

Arsenic Implantation into Polycrystalline Silicon and Diffusion to Silicon Substrate. K.Tsukamoto, Y.Akasaka, K.Horie: Journal of Applied Physics, 1977, 48[5], 1815-21