Atom-probe field-ion microscopy was used to investigate the diffusion of 3He after implantation with 300eV 3He+ ions, to a fluence of 3 x 1015/cm2, at 60 to 110K. Isothermal annealing was carried out between 90 and 110K in order to study the recovery kinetics of the 3He atoms. It was deduced that they were immobile at 60K. From the results, it was estimated that the diffusivity of 3He could be described by:

D (cm2/s) = 5.4 x 10-3 exp[-0.28(eV)/kT]

The migration enthalpy of 3He was therefore similar to that of 4He (0.24 to 0.32eV). It was also noted that self-interstitial atoms, and H, were appreciably more mobile than were 3He or 4He at a given temperature.

J.Amano, D.N.Seidman: Journal of Applied Physics, 1984, 56[4], 983-92