基于MIM结构介电薄膜电学特性表征方法研究

发布时间：2018-06-26 12:19

本文选题：介电特性 + 寄生效应　；参考：《桂林电子科技大学》2017年硕士论文

【摘要】：随着集成电路微型化,薄膜化与高频化的发展,介电薄膜得到广泛应用。但至今为止,对于高频下薄膜介电特性的精确提取,国内外还未有一个统一、完善的标准与技术。因此,介电薄膜电学特性的表征技术研究具有重要意义与较好的应用前景。高频内采用金属-绝缘-金属(简称MIM)结构表征薄膜介电特性(介电常数εr、损耗角正切值tanδ)时,表征结果不可避免地会受到寄生效应的消极影响;而薄膜介电特性准确的提取主要依赖于寄生效应的剥离。为此本文以Si02薄膜作为研究对象,针对基于MIM结构的薄膜介电特性表征方法的精确性问题展开了一系列研究:1.深入研究了薄膜介电特性的差动法表征技术。借助射频仿真软件(ADS)设计了一系列内径不同的MIM模型;并对比分析了单个结构直接表征薄膜介电特性结果,从而引出差动法表征技术的研究。文中主要探究了该方法中不同内径的MIM组合,以及MIM结构中底部电极厚度和材料对表征结果的影响。研究结果表明:1)不同内径的MIM组合得到的表征结果存在差异,其中组合DM65-55得到的εr均值为3.85,其表征精度高达98.7%;且tanδ值也在可接受范围内;2)底部电极厚度的改变对εr的影响较小,而tanδ随底部电极厚度的增加而减小;3)底部电极材料的改变对tanδ的影响较大,其值随材料导电性增加而减小。2.探究了差动法的一个补充技术——Rs剥离技术,用于剥离差动法中没作考虑的额外电阻。结果表明:经过该技术修正后的tanδ不再表现出较强的频率依赖性,其值与参考值更接近。3.对R-L等效电路法与R-Cp等效电路法进行了探究,此类方法只需采用单个MIM结构便可对介电薄膜表征过程中的寄生效应进行剥离。其中,R-L等效电路法对寄生电阻R与寄生电感L进行了提取;而R-Cp等效电路法对寄生电阻R与寄生电容Cp进行提取;二者得到的寄生电阻值相近。4.将差动法的表征结果,Rs剥离技术修正的tanδ,以及R-L等效电路法与R-Cp等效电路法的表征结果进行了对比与分析。分析结果表明:寄生电容值Cp对εr的影响比寄生电感L对εr的影响大;因此,相比R-L等效电路法,R-Cp等效电路法提取的εr均值更为理想,且与差动法得到结果相近;就tanδ计算而言,R-L等效电路法与R-Cp等效电路法得到的tanδ都较理想,且与Rs剥离技术修正后tanδ相差不大。
[Abstract]:With the development of integrated circuit miniaturization, thin film and high frequency, dielectric thin film is widely used. But up to now, there is no uniform and perfect standard and technology for accurate extraction of dielectric properties of thin films at high frequency. Therefore, the study on the characterization of dielectric thin films has important significance and good application prospect. When the dielectric properties (dielectric constant 蔚 r, loss angle tangent tan 未) of the films are characterized by metal-insulation-metal structure in high frequency, the characterization results will inevitably be negatively affected by parasitic effects. The exact extraction of dielectric properties mainly depends on the exfoliation of parasitic effect. In this paper, SiO2 thin film is taken as the object of study, and a series of studies on the accuracy of the characterization method of dielectric properties based on MIM structure are carried out. The dielectric properties of thin films were characterized by differential method. A series of MIM models with different inner diameters are designed by radio frequency simulation software (ads), and the results of direct characterization of dielectric properties of thin films with a single structure are compared and analyzed. The MIM combinations with different inner diameters and the effects of the bottom electrode thickness and the material on the characterization results of the MIM structure are mainly discussed in this paper. The results show that there are differences in the characterization results of different MIM combinations with different internal diameters, in which the 蔚 r mean of DM65-55 is 3.85, and the accuracy of characterization is up to 98.70.The tan 未 value is also within the acceptable range, and the change of electrode thickness at the bottom of DM65-55 has little effect on 蔚 r. However, the tan 未 decreases with the increase of the thickness of the bottom electrode. (3) the change of the bottom electrode material has a great effect on the tan 未, and its value decreases with the increase of the conductivity of the material. In this paper, a supplementary technique of differential method, RS stripping technique, is explored, which is used to peel off the extra resistance which is not considered in the differential method. The results show that the modified tan 未 no longer shows a strong frequency dependence, and its value is closer to the reference value of .3. R-L equivalent circuit method and R-Cp equivalent circuit method are studied. The parasitic effect in the characterization process of dielectric thin films can be stripped by using only a single MIM structure. The parasitic resistance R and the parasitic inductance L were extracted by the R- L equivalent circuit method, while the parasitic resistance R and the parasitic capacitance CP were extracted by the R-Cp equivalent circuit method. The tan 未 modified by RS stripping technique and the characterization results of R-L equivalent circuit method and R-Cp equivalent circuit method were compared and analyzed. The results show that the effect of parasitic capacitance CP on 蔚 r is greater than that of parasitic inductor L on 蔚 r, therefore, the 蔚 r mean value extracted by R-L equivalent circuit method is more ideal than that by R-L equivalent circuit method, and the result is similar to that obtained by differential method. For the calculation of tan 未, the tan 未 obtained by the R-L equivalent circuit method and the R-Cp equivalent circuit method are both ideal, and the tan 未 is not different from the modified tan 未 by the RS stripping technique.
【学位授予单位】：桂林电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.2

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