Spectromicroscopy of silicide phases formed at Ni Si interfaces

Ni/Si interfaces, produced at temperatures below (920 K) and above (1170 K) the Ni solvus line in Si have been studied by means of synchrotron radiation scanning photoelectron microscopy with spatial resolution of 0.12 mu m. The lateral distribution and composition of the formed two- (2D) and three-dimensional (3D) Ni silicide phases of micron-sized dimensions were examined. The Ni 3p chemical maps and the Si 2p, Ni 3p and valence band spectra revealed unexpected coexistence of NiSi- and NiSi(2)-like islands with distinctive shapes and orientations. The formation of these two types of islands is a common feature for both interfaces. The main difference between the interfaces was in the spatial distribution of Ni outside of the islands which showed the development of a Ni-deficient zone in the vicinity of the islands, the formation of which was favored at temperatures above the Ni solvus line. (C) 1999 Elsevier Science B.V. All rights reserved.