Comparison between Xe+ and O2+ primary ions, at low impact energy, on B delta-doping, SiGe–Si superlattice and Al/Ti multilayer structures

To improve depth resolution in secondary ion mass spectrometry (SIMS) low energy and heavy primary ions can be used. We present results obtained with xenon, at low energies (down to 500 eV), on specially chosen samples (B delta-doping, SiGe–Si superlattices and Al/Ti multilayers) to evaluate the depth resolution enhancement in ultra-shallow implants and abrupt transitions. The depth resolution parameters extracted are compared with those found with O2+ primary beam. Analyses of B delta showed an improvement for xenon at energies between 2 and 3 keV. Below 1 keV, sputter-induced roughness adversely affected the advantages of xenon. For SiGe–Si, O2+ beam, without O2 flooding remains the best choice to obtain a smaller decay length. On Al/Ti multilayers, depth profiles acquired with xenon are more suitable. This can be explained by a poor reactivity of Xe+ with metallic target atoms.