Recently, the optimisation of nickel silicides by 3^-rd element additives has appeared to become an effective way to reduce agglomeration and to retard the formation of undesirable NiSi₂ phase. Nevertheless, it puts a question on adequate identification and investigation of possible changes of NiSi properties that could be tremendous for microelectronic applications.

In our experiments, pure Ni films and Ni films with the initial concentration of 10 % of Pd were deposited on n-Si by dc magnetron sputtering system and silicidated in two step annealing procedure in the range of temperatures 475–900 ˚C.

The results of Raman and Auger (AES) measurements have shown that the introduction of small amount of Pd in NiSi in comparison with pure NiSi films retards the formation of NiSi₂ by at least 100 ˚C and enhances the technology process window up to 900˚C. Although this is a major advantage for thermostability of NiSi there are some peculiarities to note. Firstly, the presence of Pd introduces the redshift to the positions of NiSi phonon peaks in Raman spectra, i.e. Pd increases the interatomic distance of the crystal lattice in the film. Performed calculations from the mass change point of view have proved that the redshift coincides with the amount of Pd present in NiSi. We have also noted extra Raman peaks at 322 and 434 cm^-1 in NiPdSi spectra becoming more prominent with the increase of annealing temperature, which have not been reported before. We assume it is due to the disorder Raman effects, induced by Pd. Finally, we have investigated element distribution in NiSi at various temperatures and followed the diffusion of Pd element. AES spectra have shown that distribution of Pd in NiSi changes with exponential decay law at temperature increase. Although Raman spectroscopy unambiguously identifies NiSi phase, AES results indicate that there is a deviation from the equilibrium stoichiometry to the slight lack of silicon and excess of metal phase in the compound.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/15966 must be provided.