COMPOSITION CHANGES IN N-2(+) BOMBARDED TI SI BILAYERS AND MULTILAYERS - INTERPLAY BETWEEN RANDOM AND CHEMICALLY GUIDED EFFECTS/

We have studied with Auger Electron Spectroscopy and Rutherford Backsc attering Spectrometry the composition changes in Ti/Si bilayers and mu ltilayers (Ti at the surface) induced by bombardment with 30 keV N-2() ions. In addition, the chemical bonding was investigated by Auger li ne-shape analysis. In N-2(+)-bombarded systems the changes in the Si p rofiles and line shapes point to a sequence of chemical environments w ith Si-N bonds near the Ti/Si interface, quasi-elemental Si plus overs toichiometric TiN at intermediate depths, and Si-Ti bonds near the sur face. There is thus extensive transport of Si towards the surface. We conclude that chemistry plays at least four different roles in the sys tem Ti/Si: chemically enhanced transport (Si in TiN), chemically inhib ited transport (Si in Ti), bond formation in a binary situation (Si-Ti ), and bond formation in a ternary situation (TiN). The latter case co uld also be described as preferentiality in bond formation (TiN but no t Si3N4).