Chang Cheng-Hsun-Tony, Jiang Pei-Cheng, Chow Yu-Ting, Hsiao Hsi-Lien, Su Wei-Bin, Tsay Jyh-Shen
Department of Physics, National Taiwan Normal University, Taipei, 116, Taiwan.
Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan.
Sci Rep. 2019 Jun 20;9(1):8835. doi: 10.1038/s41598-019-45104-3.
Compound formation at a metal/semiconductor interface plays crucial roles in the properties of many material systems. Applications of Ni silicides span numerous areas and have the potential to be used as new functionalities. However, the magnetic properties of ultrathin Ni layers on silicon surfaces and related chemical compositions at the interface are not fully understood and the influence of Ag additives on the reactivity of Ni/Si(111) remain unclear. We report herein on the fact that the dominant species produced at the interface is NiSi, which is produced by the spontaneous formation of strong bonds between Ni and Si atoms. Assuming that a Ni layer is formed over a NiSi layer with the total coverage as a constraint, we established a chemical shift-related concentration model that, in effect, represents a practical method for determining the amount of ultrathin Ni silicides that are produced at the buried interface. The formation of Ag-Si particles provide a viable strategy for enhancing silicide formation via a specific interaction transfer mechanism, even at room temperature. The mechanism is related to differences in the enthalpies of formation ΔH, ΔH, and ΔH, for these phases and provides insights into strategies for producing ultrathin silicides at a buried interface.
金属/半导体界面处的化合物形成在许多材料体系的性质中起着关键作用。镍硅化物的应用广泛，并且有潜力用作新的功能材料。然而，硅表面超薄镍层的磁性以及界面处相关的化学成分尚未完全明确，银添加剂对Ni/Si(111)反应性的影响也仍不清楚。我们在此报告，界面处产生的主要物质是NiSi，它是由镍原子和硅原子之间自发形成强键而产生的。假设在NiSi层上形成一层镍层，并以总覆盖率为约束条件，我们建立了一个与化学位移相关的浓度模型，实际上，该模型代表了一种确定掩埋界面处超薄镍硅化物生成量的实用方法。即使在室温下，银硅颗粒的形成也为通过特定的相互作用转移机制增强硅化物形成提供了一种可行的策略。该机制与这些相的生成焓ΔH、ΔH和ΔH的差异有关，并为在掩埋界面处制备超薄硅化物的策略提供了见解。
