Study of NiSi/Si Interface by Cross-Section Transmission Electron Microscopy

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.

铁基非晶粉末对金刚石工具胎体的影响

将不同质量分数(分别为0,5%,10%和15%)的铁基非晶粉末加入铁基预合金粉末胎体中,通过热压烧结制成胎体试样后,测试其洛氏硬度、抗弯强度及磨损率。当不添加非晶粉末时,普通胎体的洛氏硬度、抗弯强度和磨损率分别为104.6 HRB,610 MPa和3.3;加入10%的非晶粉末后,其洛氏硬度和抗弯强度分别提高至107.7 HRB和965 MPa,比原胎体分别提高了3.0%和58.2%,磨损率降低至0.9,降低了72.7%;加入15%的非晶粉末后,其洛氏硬度和抗弯强度分别提高至110.0 HRB和790 MPa,分别提高了5.2%和29.5%,磨损率降低至0.6,降低了81.8%。因而铁基非晶粉末的加入可以显著提高胎体试样的机械性能和耐磨性。此外,铁基非晶粉末的DSC及XRD测试发现,在500~700℃时,铁基非晶粉末会产生晶体化相变,NiSi相中融入了B元素转化成NiSiB相,CrFe相中融入了Si元素形成SiCrFe相,都起到改善胎体结构、提高胎体性能的目的。