The diffusion of N implanted into single crystals was studied at 700 to 820C. Measurements were carried out using a method of non-destructive determination of diffusivities from the dynamics of variation in the surface impurity concentration. The initial distribution and diffusion profiles for various annealing times were determined by secondary ion mass spectrometry. The relative surface concentration of N was measured by Auger electron spectroscopy. Several fluxes of impurity atoms in the surface region of ion-doped tungsten were experimentally detected to exist. Under the assumption that the fluxes interacted with each other, the temperature dependences of the N diffusivities in the flux associated with dislocations generated by ion implantation and in the flux associated with the bulk diffusion mechanism were determined. Nitrogen diffusion was characterized by a low activation energy, namely, 0.15 and 0.75eV for dislocation and bulk mechanisms, respectively.

Nitrogen Diffusion Parameters in Ion-Implanted Tungsten Single Crystals. O.B.Bodnar, I.M.Aristova, A.A.Mazilkin, L.N.Pronina, A.N.Chaĭka, P.Y.Popov: Physics of the Solid State, 2006, 48[1], 10-4