On the ion irradiation stability of Al/Ti versus AlN/TiN multilayers

A comparative study of the structural changes induced in Al/Ti and AlN/TiN multilayers by argon ion irradiation is presented. The layers were deposited on Si substrates, by ion sputtering in case of pure metals, and reactive ion sputtering in case of metal-nitrides, to a total thickness of similar to 270 nm. The multilayered structures consisted of 10 alternative similar to 27 nm layers of each component. For ion irradiation, we used 200 keV Ar+ ions having a projected range around mid-depth of the multilayered structures. Implantations were performed at room temperature, to the fluences from 5 x 10(15) to 4 x 10(16) ions/cm(2). Structural characterization included Rutherford backscattering analysis and transmission electron microscopy. The obtained results demonstrate that AlN/TiN multilayered system exhibits a much higher irradiation stability compared to the Al/Ti system. In Al/Ti multilayers, we observe a progressed intermixing with increasing the ion fluence, the behavior being closer to the ballistic than to the thermal spike model. In AlN/TiN system, no interface mixing was registered for any of the applied irradiation fluencies. Different behavior compared to Al/Ti system is assigned to immiscibility of AlN and TiN. (C) 2008 Elsevier B.V. All rights reserved.18th International Conference on Ion Beam Analysis, Sep 23-28, 2007, Univ Hyderabad, Sch Phys, Hyderabad, Indi