Surface morphology of molybdenum silicide films upon low-energy ion beam sputtering
Surface morphology of molybdenum silicide films upon low-energy ion beam sputtering
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低能离子束溅射硅化钼薄膜的表面形貌
DOI：
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
F. Palomares
中科院分区：
文献类型：
--
作者：
R. Gago;M. Jaafar;F. Palomares
在低能 Ar+ 离子束溅射 (IBS) 后研究了硅化钼 (MoxSi1−x) 薄膜的表面形貌，以探索化合物靶上的最终图案形成，同时收集有关 IBS 硅化物辅助硅表面纳米图案化背后机制的信息。为此，通过磁控溅射制备了成分低于、等于和高于 MoSi2 化学计量 (x = 0.33) 的 MoxSi1−x 薄膜，并通过卢瑟福背散射光谱法 (RBS) 进行评估。 IBS 前后硅和硅化物薄膜的表面形态已通过原子力显微镜 (AFM) 成像，包括前者上出现典型纳米点或波纹图案的情况。在经过辐照的 MoxSi1−x 表面的情况下，AFM 在法向入射时显示出明显的表面平滑，无论是否掺入额外的 Mo（前者会在 Si 上形成纳米点图案）。形态分析也没有提供辐照 MoxSi1−x 中离子诱导相分离的证据。与硅相反，MoxSi1−x 表面在（无杂质）倾斜照射下也不会形成波纹，除非在掠入射条件下，平行波纹以比硅对应物更明显的方式出现。通过 RBS，在法向入射下用 1 keV Ar+ 照射的 MoxSi1−x 薄膜也已用于实验测量 Si 和 MoxSi1−x 材料的（绝对）溅射产率和速率。分析表明，在目前的工作条件下，硅化物的侵蚀速率大于硅，支持 TRIDYN 代码的模拟。这一发现对硅化物区域的屏蔽效应作为金属辅助硅纳米图案化中的粗糙化机制提出了质疑。相反，结果强调了原位硅化物形成的相关性。 MoxSi1−x 掠入射下波纹的形成也归因于这种几何形状下溅射效应的主导。总之，我们的工作为化合物表面的复杂形态演化提供了一些见解，并为硅化物辅助纳米图案背后的机制提供了可靠的实验证据。
The surface morphology of molybdenum silicide (MoxSi1−x) films has been studied after low-energy Ar+ ion beam sputtering (IBS) to explore eventual pattern formation on compound targets and, simultaneously, gather information about the mechanisms behind silicide-assisted nanopatterning of silicon surfaces by IBS. For this purpose, MoxSi1−x films with compositions below, equal and above the MoSi2 stoichiometry (x = 0.33) have been produced by magnetron sputtering, as assessed by Rutherford backscattering spectrometry (RBS). The surface morphology of silicon and silicide films before and after IBS has been imaged by atomic force microscopy (AFM), comprising conditions where typical nanodot or ripple patterns emerge on the former. In the case of irradiated MoxSi1−x surfaces, AFM shows a marked surface smoothing at normal incidence with and without additional Mo incorporation (the former results in nanodot patterns on Si). The morphological analysis also provides no evidence of ion-induced phase separation in irradiated MoxSi1−x. Contrary to silicon, MoxSi1−x surfaces also do not display ripple formation for (impurity free) oblique irradiations, except at grazing incidence conditions where parallel ripples emerge in a more evident fashion than in the Si counterpart. By means of RBS, irradiated MoxSi1−x films with 1 keV Ar+ at normal incidence have also been used to measure experimentally the (absolute) sputtering yield and rate of Si and MoxSi1−x materials. The analysis reveals that, under the present working conditions, the erosion rate of silicides is larger than for silicon, supporting simulations from the TRIDYN code. This finding questions the shielding effect from silicide regions as roughening mechanism in metal-assisted nanopatterning of silicon. On the contrary, the results highlight the relevance of in situ silicide formation. Ripple formation on MoxSi1−x under grazing incidence is also attributed to the dominance of sputtering effects under this geometry. In conclusion, our work provides some insights into the complex morphological evolution of compound surfaces and solid experimental evidences regarding the mechanisms behind silicide-assisted nanopatterning.
DOI：
10.1007/s00339-012-7285-8
发表时间：
2013-05-01
影响因子：
2.7
作者：
Hofsaess, H.;Zhang, K.;Broetzmann, M.
通讯作者：
Broetzmann, M.