Growth kinetics and interface structure of copper silicides studied by atom probe tomography.

Laser-assisted atom probe shows a unique potential in the analysis of embedded Si/metal interfaces, owing to its ability to deliver 3D information with atomic resolution. The interface structures in tri-layer specimens Cu/amorphous Si/Cu are investigated by this technique. For amorphous Si (a-Si) deposited on Cu, a sharp transition occurred with an interface width of 2.4 nm. On the contrary, a much broader mixed zone, 5.3 nm wide, is formed when Cu is deposited on top of a-Si. Only in the latter case, brief annealing leads to immediate nucleation of the Cu3Si. Secondary neutral mass spectrometry confirmed independently the existence of this asymmetry in phase formation and demonstrates linear growth kinetics of the silicide. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]