Fabrication of 3D fractal structures using nanoscale anisotropic etching of single crystalline silicon
Fabrication of 3D fractal structures using nanoscale anisotropic etching of single crystalline silicon
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DOI：
10.1088/0960-1317/23/5/055024
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发表时间：
2013-05-01
影响因子：
2.3
通讯作者：
Tas, Niels R.
中科院分区：
文献类型：
--
作者：
Berenschot, Erwin J. W.;Jansen, Henri V.;Tas, Niels R.
当涉及到高性能过滤、分离、阳光收集、表面电荷存储或催化时，有效表面积是最重要的。高度规则的分形结构似乎是完美的候选人，但制造可能相当麻烦。这是第一次表明，复杂的三维分形可以在单晶硅的传统微加工中使用递归操作来设计。该程序利用晶格的内置能力，以最小的构造器干扰形成自相似的八面体结构。硅分形可以直接使用，也可以作为模具将形状转移到另一种材料中。此外，它们可以是致密的、多孔的，或者像线框一样。我们证明，经过四层处理，八面体结构的初始数量增加了625倍。同时，尺寸减小了16倍，降至300纳米。在分形的八面体顶点上，可以制备出小于100nm的孔。所提出的技术支持分形的设计与豪斯多夫维数D自由选择，高达D = 2.322。
When it comes to high-performance filtration, separation, sunlight collection, surface charge storage or catalysis, the effective surface area is what counts. Highly regular fractal structures seem to be the perfect candidates, but manufacturing can be quite cumbersome. Here it is shown-for the first time-that complex 3D fractals can be engineered using a recursive operation in conventional micromachining of single crystalline silicon. The procedure uses the built-in capability of the crystal lattice to form self-similar octahedral structures with minimal interference of the constructor. The silicon fractal can be used directly or as a mold to transfer the shape into another material. Moreover, they can be dense, porous, or like a wireframe. We demonstrate, after four levels of processing, that the initial number of octahedral structures is increased by a factor of 625. Meanwhile the size decreases 16 times down to 300 nm. At any level, pores of less than 100 nm can be fabricated at the octahedral vertices of the fractal. The presented technique supports the design of fractals with Hausdorff dimension D free of choice and up to D = 2.322.