Stafiniak Andrzej, Prażmowska Joanna, Macherzyński Wojciech, Paszkiewicz Regina
Faculty of Microsystem Electronics and Photonics, Wroclaw University of Science and Technology Janiszewskiego St. 11/17 50-372 Wroclaw Poland
RSC Adv. 2018 Sep 5;8(54):31224-31230. doi: 10.1039/c8ra03711f. eCollection 2018 Aug 30.
In this work, we reported on the development of lithography-free technology for the fabrication of nanopatterned Si substrates. The combination of two phenomena, the solid-state dewetting process and metal-assisted wet chemical etching, allowed for fabrication of Si nanocolumns on large areas in a relatively simple way. The process of dewetting the thin metal layer enabled formation of nickel nanoislands, which were used as a shadow mask in the deposition of a catalytic metal pattern. Application of the two-stage dewetting process with the repetition of the metal deposition and annealing step enabled us to obtain a significant increase in the surface coverage ratio and the surface density of the nanoislands. As a catalytic metal, a gold layer was applied in the metal-assisted wet chemical etching process. The obtained columnar nanostructures showed a great verticality and had a high aspect ratio. In the conducted studies, the maximum etching rate (at RT) was higher than 1.2 μm min. The etching rate increased with increasing concentration of oxidizing (HO) and etching (HF) agent, with a tendency to saturate for more concentrated solutions. The etching rate was significantly higher for Si substrates with a crystallographic orientation (115) than for (111), but there was no privileged direction of etching except for the direction vertical to the substrate. With increasing layer thickness of the catalytic metal a decrease in the metal-assisted wet chemical etching process efficiency was observed. The developed technology allows for fabrication of patterned substrates with a wide range of lateral dimension of nanocolumns and their density.
在这项工作中，我们报道了用于制造纳米图案化硅衬底的无光刻技术的发展。固态去湿过程和金属辅助湿法化学蚀刻这两种现象的结合，使得能够以相对简单的方式在大面积上制造硅纳米柱。薄金属层的去湿过程能够形成镍纳米岛，这些镍纳米岛在催化金属图案的沉积中用作荫罩。通过重复金属沉积和退火步骤的两阶段去湿过程的应用，使我们能够显著提高纳米岛的表面覆盖率和表面密度。在金属辅助湿法化学蚀刻过程中，使用金层作为催化金属。所获得的柱状纳米结构显示出良好的垂直度且具有高纵横比。在进行的研究中，最大蚀刻速率（在室温下）高于1.2μm/min。蚀刻速率随着氧化（HO）剂和蚀刻（HF）剂浓度的增加而增加，对于更浓的溶液有饱和趋势。具有晶体取向（115）的硅衬底的蚀刻速率明显高于（111）的硅衬底，但除了垂直于衬底的方向外，没有优先的蚀刻方向。随着催化金属层厚度的增加，观察到金属辅助湿法化学蚀刻过程效率降低。所开发的技术允许制造具有广泛纳米柱横向尺寸及其密度的图案化衬底。
