INTERPLAY BETWEEN RANDOM AND CHEMICALLY GUIDED EFFECTS IN KR-BOMBARDED TI()SI BILAYERS/

Compositional changes in Ti/Si bilayers induced by bombardment with 30 keV Kr were studied with Auger electron spectroscopy and Rutherford b ackscattering spectrometry. The observed changes in the Si profiles la nd in the Auger line-shapes) indicated a sequence of chemical environm ents with mixed Ti/Si at greatest depths, a phase similar to TiSi2 at intermediate depths and mixed Ti/Si at the smallest depths. In contras t to bombardments with N-2(+) as reported in a previous work, there is no tendency for Si to be transported to the surface. By changing the thickness of the Ti film over the Si substrate while maintaining the s ame Kr implantation conditions, it was established that TiSi2 formatio n occurs well beyond the Kr range (15.5 nm), and it was inferred that defect migration with a range of 40-70 nm contributes significantly to the mixing. An explicit indication for chemical effects at elevated t emperatures was notably absent: thermal-spike effects certainly occurr ed, but these were not prominent. (C) 1998 Elsevier Science S.A.