The isothermal migration of I in TiN was studied by implanting 800keV I++ ions in sintered samples at an ion fluence of 5 x 1015/cm2. Thermal treatments were performed under secondary vacuum at temperatures ranging from 1200 to 1700C. Iodine concentration profiles were determined by 2.5MeV α-particle elastic backscattering. The migration of I seems to be correlated with point defects created by implanted ions near the surface. The Arrhenius plot corresponding to I de-trapping was curved with possibly two straight-line regions which could indicate either the presence of two types of traps, or a strong dependence of trap’s concentration on temperature above 1500 °C. The activation energies associated with each linear region of the Arrhenius plot were found to be: Ea = 2.4eV below 1500C and Ea = 11.4eV above 1500C. Nitrogen evaporation from TiN surface under secondary vacuum was proposed as a contributing factor to the enhanced mobility of iodine at high temperature.

Iodine Isothermal Migration Behaviour in Titanium Nitride. S.Gavarini, H.Jaffrezic, P.Martin, C.Peaucelle, N.Toulhoat, S.Cardinal, N.Moncoffre, C.Pichon, M.Tribet: Journal of Nuclear Materials, 2008, 374[1-2], 320-6