The diffusivity in polycrystalline films was studied by using a novel bilayer structure which consisted of a polycrystalline Si layer which was doped in situ with As and was deposited onto an undoped polycrystalline Si layer. This technique avoided the complication of structural changes that resulted from ion implantation. The diffusivity was measured at 700 to 850C, and could be described by:

D (cm2/s) = 1.0 x 101 exp[-3.36(eV)/kT]

The deviation from this relationship was less than 20%. The values were about 3 orders of magnitude greater than intrinsic As diffusivity in the Si lattice. It was suggested that diffusion occurred along grain boundaries, and that background impurities in the grain boundaries were responsible for the large reported variations in data.

M.Arienzo, Y.Komem, A.E.Michel: Journal of Applied Physics, 1984, 55[2], 365-9

The best linear fits to the solute diffusion data ([124] to [129], [133] to [144], [146] to [176], [188] to [192], [196] to [211], [215] to [223], [234] to [242], [252] to [283], [292] to [298], [306] to [314]) yield:

Al: Ln[Do] = 0.45E – 32.8 (R2 = 0.81); As: Ln[Do] = 0.29E – 23.2 (R2 = 0.87);

Au: Ln[Do] = 0.16E – 12.4 (R2 = 0.16); B: Ln[Do] = 0.29E – 22.6 (R2 = 0.79);

Cu: Ln[Do] = 0.22E (R2 = 0.86); Fe: Ln[Do] = 0.62E – 15.8 (R2 = 0.53);

Ga: Ln[Do] = 0.20E - 16.9 (R2 = 0.78); Ge: Ln[Do] = 0.29E – 23.2.8 (R2 = 0.98);

H: Ln[Do] = 0.17E - 9.9 (R2 = 0.07); Li: Ln[Do] = 0.25E – 9.6 (R2 = 0.48);

Ni: Ln[Do] = 0.29E - 19.4 (R2 = 0.66); O: Ln[Do] = 0.34E – 21.6 (R2 = 0.95);

P: Ln[Do] = 0.35E - 27 (R2 = 0.94); Sb: Ln[Do] = 0.35E – 29.3 (R2 = 0.96);

Si: Ln[Do] = 0.33E - 29 (R2 = 0.86)