Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.

This work clearly demonstrates that the X Ray Reflectometry technique (XRR), extensively used to assess the quality of microelectronic devices can be a useful tool to study the first stages of ion beam mixing. This technique allows measuring the evolution of the Si concentration profile in irradiated Cr/Si layers. From the analysis of the XRR profiles, it clearly appears that the Si profile cannot be described by a simple error function.

We present in this text a new experimental tool to study the mixing of atoms under irradiation. Based on physics of x ray diffraction, the specular reflectivy of x ray was used to estimate the Auto Correlation Function associated with the electron density gradient. The accuracy of the ACF is around 1 nanometer and does not evolve with the thickness of the probed layer. Thus, this point allows accurately measuring the broadening of the electron density gradient spreading induced by irradiation. Such an accurate profile extracted over a large range of fluences (about 3 decades) would lead to the determination of the functional dependence of this spreading with the fluence. This could allow pointing out the main mechanisms triggering the atomic mixing over large distances when atomic mixing occurring in thermal spikes is washed out.

Nitrogen implantations in pure iron and various stE-els are investigated using nuclear reaction analysis, Conversion Electron M6ssbauer Spectroscopy and Grazing angle X-ray Diffraction. The present work sums up all the significant results although it does not constitue a systematic study. It describes the influence of the chemical composition and the structure effect of the matrix as well as those of the implantation time. The N-martensite, ε-nitride and ε-carbonitride phases are principally identified. The fraction of iron bound with nitrogen is evaluated in the different steels. The strong influence of the small chromium amounts inside the matrix upon the nitride formation is underlined. A preferential orientation of these phases is shown. SIMS experiments are presented in particular to determine the carbon distribution in the first surface layers.