标题: Ti/NiSi/Si及TiN/NiSi/Si堆叠结构
The Thermal Stability of Ti/NiSi/Si and TiN/NiSi/Si Stack Structures
作者: 陈朝钦
Chen Chao-Chin
雷添福
Lei Tan-Fu
电子研究所
关键字: 堆叠结构;Ti, Ni, TiN;Stack Structures;Ti, Ni, TiN
公开日期: 2000
摘要: 本论文中,我们主要探讨矽化镍(NiSi)的材料特性与应用于超大积体电路上的相关制程技术。首先是探讨矽化镍的片电阻效应热稳定性,当制程温度超过700℃时,矽化镍片电阻的大幅上升将会限制其在高温制程上的应用。因此为了改善矽化镍的特性,我们用了两种多层堆叠金属结构来增加矽化镍的热稳定性,分别是钛/镍/矽(Ti/Ni/Si)和氮化钛/镍/矽(TiN/Ni/Si)。含钛和氮化钛的多层金属结构很明显的改善了矽化镍在片电阻方面的热稳定性。以钛为保护层的矽化镍P/N接面可以在钛的保护下,阻挡了在矽化的过程中氧原子的进入。而以氮化钛为保护层的P/N接面则是因为氮化钛中的氮和矽反应产生氮化矽层,所以在矽化过程中氮化矽层阻挡了氧原子的进入。因此含钛以及含氮化钛的多层金属结构下的矽化镍片电阻特性非常相似,其在800℃高温处理下仍能保持稳定的低片电阻值。此外我们也探讨氟离子或氮离子的植入对矽化镍影响。在形成P/N接面之前,先利用氮离子或氟离子的植入来改善矽化镍的特性,提高了矽化镍在高温应用上的可能性。我们发现到氟离子的植入可以让矽化镍的片电阻在制程温度超过800℃时才开始大幅上升。而且有氮离子和氟离子植入之P/N接面的漏电流也比没有植入的减小了许多。这是因为氮离子和氟离子减缓了镍跟矽的反应,使得矽化镍(NiSi)转变为矽化二镍(Ni2Si)的温度大幅提高。
In this thesis, we have studied basic material properties of nickel silicide and some key process technology relevant to ULSI applications. First, sheet resistance behavior of Ni silicide was investigated. The degradation of sheet resistance occurred at 700ºC limits the applications of Ni silicide in high temperature procedure. In order to improve the performance of Ni silicide films, we proposed two kinds of bilayer structures, Ti/Ni/Si and TiN/Ni/Si, to improve the thermal stability of NiSi. Ti- and TiN-contained bilayer structures clearly improved the thermal stability of sheet resistance. Ni silicide p+/n junction using Ti as a capping layer can suppress oxygen contaminant during silicidation. And Ni silicide p+/n junction using TiN as a capping layer can form a nitride layer to prevent NiSi oxidation. Hence, the characteristics of sheet resistance for Ti- and TiN-contained bilayer structures are very similar. It can maintain a low sheet resistance after 800ºC RTA treatment. Moreover, the influence of nitrogen or fluorine implantation on Ni silicide was also considered. Nitrogen or fluorine implanted before p+/n junction formation can improve the thermal stability, and enhanced the possibility of applications to Ni silicide in high temperature procedure. We find that fluorine implantation can slow down sheet resistance degradation of Ni silicide and let it greatly increase only after 800ºC annealing. Besides, with fluorine or nitrogen implantation also reduced the leakage current of Ni silicide p+/n junction. This is because that nitrogen and fluorine retarded the reaction of Ni and Si, and the temperature for NiSi transforming into NiSi2 was increased.
URI: http://140.113.39.130/cdrfb3/record/nctu/#NT890428112
http://hdl.handle.net/11536/67188
显示于类别:Thesis