In situ interferometric depth and topography monitoring in LIBS elemental profiling of multi-layer structures

Abstract

Depth-resolved analysis of multi-layer structures is carried out by employing Laser Induced Breakdown Spectroscopy (LIBS) in combination with white light interferometry, which enables accurate, in situ depth monitoring. The proposed system combines the LIBS optical setup with the interferometer and is capable of following the LIBS experiment pulse-to-pulse, providing in situ accurate depth measurement as well as detailed crater profile mapping. The elemental information extracted from the LIBS spectrum can be correlated directly to the depth and topography measurement resulting in the accurate mapping of the elemental profile along the normal to the sample surface. Details on the optical setup along with several examples on elemental depth profile analysis are presented; issues regarding the speed of depth monitoring and limitations of the setup are discussed.