Different silicidation processes are employed to form NiSi,and the NiSi/Si interface corresponding to each process is studied by cross-section transmission electron microscopy (XTEM). With the sputter deposition of a nickel thin film,nickel silicidation is realized on undoped and doped (As and B) Si(001) substrates by rapid ther mal processing (RTP). The formation of NiSi is demonstrated by X-ray diffraction and Raman scattering spectros- copy. The influence of the substrate doping and annealing process (one-step RTP and two-step RTP) on the NiSi! Si interface is investigated. The results show that for one-step RTP the silicidation on As-doped and undoped Si substrates causes a rougher NiSi/Si interface,while the two-step RTP results in a much smoother NiSi/Si interface. High resolution XTEM study shows that axiotaxy along the Si(111) direction forms in all samples, in which specific NiSi planes align with Si(111) planes in the substrate. Axiotaxy with spacing mismatch is also discussed.
In order to clarify the effect of pt addition on the stress of NiSi film, in situ stress measurements were taken to evaluate the stress evolution during heating and cooling treatment of Ni1- x Ptx Si alloy films with different Pt concentrations. The room temperature stress, which is mainly thermal stress, was measured to be 775MPa and 1.31GPa for pure NiSi and pure PtSi films grown on Si (100) substrates,respectively. For Ni1-x Ptx Si alloy film, the room temperature stress was observed to increase steadily with Pt concentration. From the temperature dependent stress evolution curves,the stress relaxation temperature was found to increase from 440℃ (for pure NiSi film) to 620℃ (for pure PtSi film) with increasing Pt concentration, thus influencing the residual stress at room temperature.