Chemical Composition of Advanced Materials as Obtained by the 3-Dimensional Atom Probe

Abstract

The 3-dimensional atom probe is based on field ion microscopy where the screen is replaced by a 2-dimensional, position sensitive detector. Atoms were removed from a conducting sample by a high voltage pulse. The time of flight reveals their chemical nature, and continuous stripping allows lateral and in-depth analysis. The spatial resolution permits a chemical analysis on the sub-nanometer scale. Results of this new technique are presented for (i) the initial stages of interdiffusion at the boundary between two metals, (ii) P-segregation at grain boundaries in nanocrystalline Ni-P alloys, (iii) initial stages of nucleation and growth in various alloys, (iv) composition of thin oxide films in TMR-structures, and (v) distribution of hydrogen in metallic multilayers. It will be also shown that the new technique not only allowed a characterization on the atomic scale but verified and/or falsified existing models for the examples given before.