Initial stages of Ni reaction on Si 100/and H-terminated Si 100/ surfaces

Initial stages of Ni reaction both on Si 100.and hydrogen H.-terminated Si 100.- 2=1.-H surfaces have been studied using scanning tunneling microscopy STM.. STM images reveal that deposited Ni atoms react directly with Si atoms on the clean surface and induce defective sites, while those on the H-terminated surface are prevented from reacting with Si atoms and forms clusters. In the latter case, we find a new adsorption site of Ni atom which sticks in dimerised Si atoms, causing the dimer splitting into both sides. It is also found that, in the case of the deposition on the clean surface followed by annealing, the Si substrate surrounding NiSi2 island is rather disordered, while on the H-terminated surface, the surface shows a homogeneous 2=n.structure, reflecting the surface morphology at the initial stages of Ni reaction. q1998 Elsevier Science B.V. All rights reserved