Use of Auger imaging for three‐dimensional visualization of interface morphology at isoconcentration

Depth or line profiles on polished sections only provide partial and local information about the chemical distribution at the interface between two solids. Germination and growth, which happen during the reaction phase, can only be explored by a three-dimensional in-situ visualization. The most powerful means presently at our disposal are: (i) for non-destructive analysis, synchrotron microtomography, with a maximum lateral resolution of 0.29 μm (ESRF, European Synchrotron Radiation Facility, Grenoble, France), and, (ii) for destructive analysis, SIMS image reconstruction (resolution 0.2 μm), with a difficult quantitative interpretation. The object of this paper is to demonstrate that a 3D analysis of a series of AES images is possible at an unrivalled spatial resolution (lateral and depth) and coupled with chemical analysis. The interaction between titanium and carbon at moderate temperatures is considered here to illustrate the method. The sample is elaborated from a polished substrate of carbon on which a thin layer of titanium is deposited by PVD. Thereafter the sample has been thermally treated under secondary vacuum. The data set comprises 50 images (squares of side 7 μm) separated by 20 nm, yielding to an analysis volume corresponding to a parallelepiped of 7x 7x 1 μm 3 . On a sample maintained at 450°C for 30 min, the formation of TiC islands on a thickness of about 100 nm has been observed.