| 摘要: | 在互補式金氧半電晶體元件尺寸日益縮小的趨勢下，自我對準金屬矽化物製程(self-aligned silicidation process)相關技術已經面臨製程上的極限。近幾年來金氧半場效電晶體為了增加其元件效能，因此利用磊晶金屬矽化物(epitaxial metal silicide)源/汲極結構來取代先前的金屬矽化物源/汲極，而且可以在矽化物/矽接面處形成相當平整的磊晶矽化物以有效的降低接觸面的接觸電阻(contact resistance)。而有研究指出當金屬Ni厚度小於某一臨界厚度即可在低溫下生成磊晶二矽化鎳(Epi- NiSi2)而不需經過其他中間相。根據上述之現象，本研究探討以磁控濺鍍沉積系統所製備出之不同鎳合金元素的薄膜，包含Ni1-xPtx/ Si、Ni1-yTiy/ Si及Ni1-zAlz/ Si三個系統並針對其超薄鎳合金磊晶矽化物之生成行為，並藉由摻雜不同元素探討其二矽化鎳生成行為之影響作一深入探討。本研究發現在鍍膜後將金屬蝕刻掉會留下一層超薄的鎳矽混合層(Ni-Si intermixed layer)，再經過退火的處理可以在低溫下生成超薄的磊晶二矽化鎳(Epi- NiSi2)，經由此方法生成的磊晶可以避免大量的倒金字塔結構產生，相信對其漏電流的影響會有所改善。搭配各種材料分析方法如：四點探針、背向散射電子繞射儀、掃描式電子顯微鏡、光電子能譜儀、穿透式電子顯微鏡觀察超薄鎳合金磊晶矽化物的電性、晶格對稱性、表面型態、鍵結分析、合金元素分布情形以及原子級微結構，經由本實驗可以得知超薄鎳合金磊晶矽化物應用在先進的金氧半場效電晶體的源極/汲極之接觸是相當有發展性的材料。As the complementary metal-oxide-semiconductor (MOS) transistor device size shrinked, self-aligned silicidation process have been faced with the limitation on the process. Recently, in order to increase MOSFET device performance, conventional metal silicide source/drain was replaced by epitaxial metal silicide source/drain structures, formed quite flat epitaxial silicide and effectively reduced the contact resistance in the silicide/silicon junction. It reported that the thickness of nickel is less than a critical thickness, epitaxial nickel disilicide can be generated at low temperatures without passing through other intermediate phase. According to the above phenomenon, the study was investigated through the different nickel alloy epitaxial silicide formation mechanism and the effect of different doping elements, which was prepared by magnetron sputter deposition system including the Ni1-xPtx/Si, Ni1-yTiy/Si and Ni1-zAlz/Si systems. It was found that after depositing and then metal etching a nickel-silicon would be leaved as a mixed layer. Subsequent annealing at low temperature of a mixed layer resulted in an ultrathin epitaxial nickel disilicide, which suppressed a lot of inverted pyramid structures and the leakage currents. The electrical properties, lattice symmetry, surface morphology, bonding analysis, alloying elements distribution and atomic-scale microstructure were then analyzed by four point probe, electron back-scattered diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy, transmission electron microscopy, respectively. An ultrathin nickel alloy epitaxial silicide is the promising material for the application in advanced metal-oxide MOSFET source/drain contact. |
