Formation mechanism of silicon surface nanoholes

硅表面纳米孔的形成机制

• 批准号: 10305006
• 负责人: TAKEDA Seiji
• 金额: $ 25.86万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A).
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10305006/
• 关键词: silicon; surface; nanostructures; electron irradiation; point defects; ナノストラクチュア

The aim of this research project is to elucidate the formation mechanism of silicon surface nanoholes, which are introduced on silicon surface by high energy electron irradiation. Preliminary studies on the formation of nanoholes were carried out soon after the finding of surface nanoholes by the principal investigator of the research project. Supported by the grant, the systematic studies were made possible by means of transmission electron microscopy and scanning tunneling microscopy. Based on the substantial experimental data along with computer simulation, we have shown that the formation process of surface nanoholes is classified in the three stages. 1) The minimum electron energy needed for the formation of nanoholes has been determined to be 30keV.This shows that, as the primary event of the nanohole formation, single Si atoms on a surface are sputtered out, leaving surface vacancies behind. 2) Under electron irradiation, surface vacancies can migrate athermaly as well as thermally in the wide temperature range from 4 to 500K.3) Nanoholes are gradually excavated along the direction of ongoing electrons with the increase of electron dose. The peculiar phenomenon is accounted for by the anisotropic diffusion of surface vacancies via the momentum transfer from electrons to Si atoms located on the wall of nanohoels. The present study has clarified that the dynamic nature of atoms on surface at the states far from the equilibrium, which has been much less described so far.During the experiments which were proposed in the project, we have found a new phenomenon that electron irradiation renders crystalline silicon to amorphous silicon. The mechanism of the amorphization is also accounted for by the clustering of point defects under electron irradiation.The present study will be a basis for fabrication of nanostructures and Si-based microelectronic devices, since an electron beam can be focused on an area smaller than nano-meters and scanned easily.

该研究项目的目的是阐明通过高能电子辐照在硅表面引入纳米孔的硅表面纳米孔的形成机制。该研究项目的主要研究者在发现表面纳米孔后不久就对纳米孔的形成进行了初步研究。在该资助的支持下，通过透射电子显微镜和扫描隧道显微镜进行了系统研究。基于大量的实验数据和计算机模拟，我们表明表面纳米孔的形成过程分为三个阶段。 1）形成纳米孔所需的最小电子能量被确定为30keV。这表明，作为纳米孔形成的主要事件，表面上的单个Si原子被溅射出来，留下表面空位。 2)在电子辐照下，表面空位在4~500K的宽温度范围内可以发生非热迁移和热迁移。3)随着电子剂量的增加，纳米孔沿着电子运动方向逐渐被挖出。这种奇特的现象是由电子到位于纳米孔壁上的硅原子的动量转移引起的表面空位的各向异性扩散造成的。本研究阐明了表面原子在远离平衡态时的动态性质，迄今为止对此的描述要少得多。在该项目提出的实验中，我们发现了一种新现象，即电子辐照呈现晶体硅到非晶硅。非晶化的机制也可以通过电子辐照下点缺陷的聚集来解释。本研究将成为纳米结构和硅基微电子器件制造的基础，因为电子束可以聚焦在比纳米更小的区域上。 - 米并轻松扫描。

项目成果

N.Ozaki,Y.Ohno,M,Tanbara,D.Hamada,J.Yamasaki & S.Takada: "Observation of silicon surface nanoholes by scanning tunneling microscopy"Surface Science. (accepted for publication).

N.Ozaki,Y.Ohno,M,Tanbara,D.Hamada,J.Yamasaki

H.Kohno,T.Iwasaki & S.Takada: "Metal-mediated growth of alternate semiconductor-insulator nanostructures"Solid State Communications. 116. 591-594 (2000)

H·河野,T·岩崎

H.Kohno and S.Takeda: "Periodic instability in growth of chairs of crystalline-silicon nanospheres"J.Crys.Grocoth. 216. 185-191 (2000)

H.Kohno 和 S.Takeda：“晶体硅纳米球椅生长的周期性不稳定”J.Crys.Grocoth。

N.Aki,Y.Ohno,H.Kohno & S.Takada: "Formation of microcracks in cubic boron nitride"PhiBos.Mag.A59. A59. 2694-2699 (2000)

N.Aki,Y.Ohno,H.Kohno

S.Takeda and J.Yamasaki: "Amorphigathe in silicon by electron irradiation"Phys.Rov.Lett.. 83. 320-323 (1999)

S.Takeda 和 J.Yamasaki：“通过电子辐照在硅中形成无定形”Phys.Rov.Lett.. 83. 320-323 (1999)