Solid-state reactions in 200 nm Ti/200 nm Ni thin-film system on (001) Si are investigated by X-ray diffraction, cross-sectional transmission electron microscopy (XTEM), and electrical-resistance measurement. The goal of this work is to find out the influence of a superficial layer of Ti on the stability of NiSi silicide formation. Samples were annealed in the temperature range from 470 to 1270 K for 1 h. X-ray diffraction is used for phase identification. XTEM, TEM, and four-point probe electrical-resistance measurement are used to study the morphology and microstructure changes. As revealed after annealing at 470 K, there is a formation of amorphous particles of size of 200 nm. At annealing up to 670 K, they begin to crystallize into the NiSi phase. At the same time, the intermetallic Ni3Ti is formed. After annealing at 1070 K for 1 h, the NiSi persists without transition to NiSi2, and its stability is demonstrated by the low resistivity of 9 μω-cm, which does not change even at 1070 K for 2 h. After annealing at 1270 K for 1 hour, both NiSi and small amount of NiSi2 can be observed with X-ray diffraction, but the NiSi is still the predominant phase.
|Journal||Metallofizika i Noveishie Tekhnologii|
|State||Published - 1 May 2003|