Dual mechanism of ion beam mixing of noble metals with oxide matrices

Layers of noble metals M embedded in various oxide matrices (SiO₂, Al₂O₃, TiO₂, ZrO₂, and also Si for a purpose of comparison) were irradiated with incremented fluences of MeV heavy ions. A major contribution of recoil implantation to displacements accounts for the linear rates of atoms relocation as a function of the ion fluence, measured by means of RBS. According to the temperature and to the initial thickness of the M layer, the in depth-straggling of M atoms varies in proportion to the ion fluence or to its square. This change of straggling rate is explained by its control either by the radiation-enhanced diffusion or by the recoil implantation process, when the solution of diffusion equations relative to an infinitely thin source cannot be applied. The mobility of M atoms in the oxide depends on the latter ionicity and on the M mass.