Thin Ni silicide formation by low temperature-induced metal atom reaction with ion implanted amorphous silicon

摘要

We have extended our recent work on buried silicide formation by Ni diffusion into a buried amorphous silicon layer to the case where silicide formation is at lower temperatures on silicon substrates which have been preamorphized. The reaction of metal atoms from a 12 nm Ni film evaporated on top of a 65 nm thick surface amorphous layer formed by 35 keV Si(sup +) ion implantation has been investigated at temperature (le)400C. Rutherford Backscattering Spectrometry (RBS) with channeling, cross-sectional transmission electron microscopy (XTEM), x-ray diffraction and four-point-probe measurements were used to determine structure, interfacial morphology, composition and resistivity of the silicide films. It has been found that an increased rate of silicidation occurs for amorphous silicon with respect to crystalline areas permitting a selective control of the silicon area to be contacted during silicide growth. Vacuum furnace annealing at 360C for 8 hours followed by an additional step at 400C for one hour produces a continuos NiSi(sub 2) layer with a resistivity 44 (mu)(Omega) cm.