Abstract
The effects of Ti interlayer on the formation of Ni silicides on Si(100) substrate is investigated. The thermal stability and microstructure of Ni silicides are characterized by in-situ curvature measurement, x-ray diffraction, Auger electron spectroscopy, four-point probe method, and transmission electron microscopy.In the Ni(30 nm)/Ti(3 nm)/Si system, it was found that at 359 ℃, Ni diffuses through the Ni-Ti-Si mixed layer to reach Si substrate. The transformation temperature for the NiSi are significantly increased while the transformation temperature for NiSi to NiSi2 formation remains the same at 795 ℃. The temperature range of the NiSi phase is shorted by addition of a Ti interlayer. As the thickness increasing, although the transformation temperature of NiSi is higher, Ti interlayer with 5 nm thickness is the limit. Even with a 10 nm thick Ti interlayer, the transformation temperature of NiSi is roughly the same as that with a 5 nm thick Ti interlayer.The Ni-Ti-Si continued mixed layer on the surface inhibited the stress relaxation mechanisms for NiSi. Nevertheless, the Ti interlayer significantly improved the epitaxial quality of NiSi2 on Si (100) substrate with stepwise interfaces .