Chen Ming, Pethö Laszlo, Sologubenko Alla S, Ma Huan, Michler Johann, Spolenak Ralph, Wheeler Jeffrey M
Laboratory for Nanometallurgy, Department of Materials Science, ETH Zürich, Vladimir-Prelog-Weg 5, 8093, Zürich, Switzerland.
Laboratory for Mechanics of Materials and Nanostructures, Empa, Swiss Federal Laboratories for Materials Science and Technology, Feuerwerkerstrasse 39, 3602, Thun, Switzerland.
Nat Commun. 2020 May 29;11(1):2681. doi: 10.1038/s41467-020-16384-5.
As the backbone material of the information age, silicon is extensively used as a functional semiconductor and structural material in microelectronics and microsystems. At ambient temperature, the brittleness of Si limits its mechanical application in devices. Here, we demonstrate that Si processed by modern lithography procedures exhibits an ultrahigh elastic strain limit, near ideal strength (shear strength ~4 GPa) and plastic deformation at the micron-scale, one order of magnitude larger than samples made using focused ion beams, due to superior surface quality. This extended elastic regime enables enhanced functional properties by allowing higher elastic strains to modify the band structure. Further, the micron-scale plasticity of Si allows the investigation of the intrinsic size effects and dislocation behavior in diamond-structured materials. This reveals a transition in deformation mechanisms from full to partial dislocations upon increasing specimen size at ambient temperature. This study demonstrates a surface engineering pathway for fabrication of more robust Si-based structures.
作为信息时代的支柱材料，硅在微电子和微系统中被广泛用作功能半导体和结构材料。在环境温度下，硅的脆性限制了其在器件中的机械应用。在此，我们证明，通过现代光刻工艺加工的硅在微米尺度上表现出超高的弹性应变极限、接近理想的强度（剪切强度约为4 GPa）和塑性变形，由于表面质量优异，其塑性变形比使用聚焦离子束制备的样品大一个数量级。这种扩展的弹性状态通过允许更高的弹性应变来改变能带结构，从而增强了功能特性。此外，硅的微米尺度塑性使得能够研究金刚石结构材料中的固有尺寸效应和位错行为。这揭示了在环境温度下，随着试样尺寸的增加，变形机制从全位错向部分位错的转变。这项研究展示了一种用于制造更坚固的硅基结构的表面工程途径。
