Investigation of ion-beam mixing in Ti:Al bilayered samples

Ion beam mixing in thin bilayered samples of Ti:Al by 100 keV argon ions at low temperature has been studied. The samples were prepared by sequential e-beam evaporation of about 500 nm of aluminium and a layer of titanium with different thickness onto single craystals of Si. The samples were bombarded with ions under the doses ranging from 1.2 x 1016 to 1.4 x 1017 ions/cm2 and analysed by RBS using a 2 MeV 4He beam. It is discovered that the mixing has caused broadening of the aluminium front edge and the titanium back edge in the RBS spectrum and the interfacial broadening increases clearly with ion doses. The mixing broadening of the Ti:Al interface has a square-root dependening on argon fluence, and under the same bombarding conditions the square of mixing broadening is related to the thickness of the Ti layer. It is found that the mixing is influenced by the presence of the interfacial oxide layer between the titanium and aluminium layers. The experimental results are compared with Monte Carlo computer simulations and the mixing process is discussed in detail