Depth profile analysis of nanometric layers by laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) was applied to depth profile analysis and thickness measurements of a nanometric copper layer deposited on a steel substrate. In this technique, several laser pulses are successively delivered to the same position of the layer surface. It was shown that a minimum ablation rate was achieved at a laser pulse energy of 7 mJ and a lens-to-sample distance (LTSD) of 33 mm (target was moved 2 mm from the focal point toward a lens).