Spectromicroscopy of interfacial interactions between thin Ni films and a Au-Si surface

The interaction between a(root3 x root3)R30 degrees -Au/Si surface with thi n (less than or equal to2 ML) Ni films with different dimensions deposited at 300 K is studied by means of a scanning photoelectron spectromicroscopy. The interfacial processes occurring at different Ni coverages and annealin g temperatures are probed with lateral resolution of 0.12 mum. The results have revealed that Ni displaces Au from the Si surface and the presence of Au lowers the formation temperature of the Ni disilicide phase. It has been found that the behavior of the Ni/Au-Si interfaces at high temperatures, i n particular the changes in the morphology of the interface and the formati on of well defined Ni-x(Au1-x)Si-2 islands, is strongly influenced by the d imensions of the Ni patches. The observed evolution of the Ni/Au-Si interfa ces is interpreted considering the high solubility of Ni in Si, the miscibi lity between Ni and Au and the Au-Si alloying at elevated temperatures. (C) 2001 Elsevier Science B.V. All rights reserved.