Kopycinska-Müller M, Clausner A, Yeap K-B, Köhler B, Kuzeyeva N, Mahajan S, Savage T, Zschech E, Wolter K-J
Fraunhofer Institute for Ceramic Technologies and Systems - Material Diagnostics IKTS-MD, Maria Reiche Str. 2, 01109 Dresden, Germany; Faculty of Electrical Engineering and Information Technology, Technical University Dresden, Helmholtz Str. 18, 01069 Dresden, Germany.
Fraunhofer Institute for Ceramic Technologies and Systems - Material Diagnostics IKTS-MD, Maria Reiche Str. 2, 01109 Dresden, Germany.
Ultramicroscopy. 2016 Mar;162:82-90. doi: 10.1016/j.ultramic.2015.12.001. Epub 2015 Dec 9.
The indentation modulus of thin films of porous organosilicate glass with a nominal porosity content of 30% and thicknesses of 350nm, 200nm, and 46nm is determined with help of atomic force acoustic microscopy (AFAM). This scanning probe microscopy based technique provides the highest possible depth resolution. The values of the indentation modulus obtained for the 350nm and 200nm thin films were respectively 6.3GPa±0.2GPa and 7.2GPa±0.2GPa and free of the substrate influence. The sample with the thickness of 46nm was tested in four independent measurement sets. Cantilevers with two different tip radii of about 150nm and less than 50nm were applied in different force ranges to obtain a result for the indentation modulus that was free of the substrate influence. A detailed data analysis yielded value of 8.3GPa±0.4GPa for the thinnest film. The values of the indentation modulus obtained for the thin films of porous organosilicate glasses increased with the decreasing film thickness. The stiffening observed for the porous films could be explained by evolution of the pore topology as a function of the film thickness. To ensure that our results were free of the substrate influence, we analyzed the ratio of the sample deformation as well as the tip radius to the film thickness. The results obtained for the substrate parameter were compared for all the measurement series and showed, which ones could be declared as free of the substrate influence.
借助原子力声学显微镜（AFAM）测定了标称孔隙率为30%、厚度分别为350nm、200nm和46nm的多孔有机硅酸盐玻璃薄膜的压痕模量。这种基于扫描探针显微镜的技术提供了尽可能高的深度分辨率。350nm和200nm薄膜的压痕模量值分别为6.3GPa±0.2GPa和7.2GPa±0.2GPa，且不受基底影响。对厚度为46nm的样品进行了四个独立的测量组测试。在不同的力范围内使用了两种不同尖端半径（约150nm和小于50nm）的悬臂，以获得不受基底影响的压痕模量结果。详细的数据分析得出最薄薄膜的压痕模量值为8.3GPa±0.4GPa。多孔有机硅酸盐玻璃薄膜的压痕模量值随薄膜厚度的减小而增加。多孔薄膜中观察到的硬化现象可以用孔隙拓扑结构随薄膜厚度的变化来解释。为确保我们的结果不受基底影响，我们分析了样品变形以及尖端半径与薄膜厚度的比率。对所有测量系列的基底参数结果进行了比较，并表明哪些结果可以被视为不受基底影响。
