An investigation was made of B out-diffusion under various conditions. It was found that the out-diffusion was significant in an H2 ambient, whereas it was negligible in N2 or He. The diffusivity of B in an H2 ambient was found to be lower than that in an N2 ambient. Significant B out-diffusion in an H2 ambient was attributed to an enhancement of the B transport coefficient at the Si surface. The diffusivity of B in an H2 ambient could be described by:

D (cm2/s) = 9.07 x 102 exp[-4.4(eV)/kT]

Negligible out-diffusion in N2 and He ambients was attributed to a negligible transport coefficient at the surface.

K.Suzuki, H.Yamawaki, Y.Tada: Solid-State Electronics, 1997, 41[8], 1095-7