TRANSMISSION ELECTRON MICROSCOPE STUDY OF INTERNAL STRESSES AT RECONSTRUCTED CLEAN AND METAL ADSORBED SURFACES

重建清洁金属吸附表面内应力的透射电子显微镜研究

• 批准号: 05452037
• 负责人: YAGI Katsumichi
• 金额: $ 4.1万
• 依托单位: TOKYO INTITUTE OF TECHNOLOGY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05452037/
• 关键词: Internal surface stress; Surface strain; Si (001) 2x1; Transmission elect. microsc.; Reflection elect. microsc.; 反射電顕法; 表面再構成; 吸着構造; Si(111); Si(111)5x2-Au

Transmission electron microscopy (TEM) in an ultra-high vaccuum condition can reveal structures of surfaces and surface dynamic processes. One of the characteristics of the technique is in that it can characterize internal surface stresses at surfaces which are due to surface reconstruction. Most of the surface recon-structions and adosrbate structures, if it is free from the substrates are not always have the same lattice period with that of the substrate lattice underneath. This is the origin of the interna lsurface stresses. This causes bending of thin crystal films. Inversely, on the bend crystals surface structures or surface structure domians which favor such strain nominates. In the former cases, multi-domain formation does not cause bending even in cases of strong internal tress. TEM can see lattice strain caused by internal surface stress.Our observations were summarized as follows.(1) Si (111) 4x1-In structure does not have internal stress.(2) Si (001) 2x1 surface is anisotro … More pically stressed.(3) Si (111) 7x7 structure is under a delatational stress and phase boundaies between 7x7 and 1x1 structure have strong lattice strain.(4) Si (111) 5x2-Au surface has anisotropic lattice stress. Domain boundaies of the 5x2 structure have strong strain contrast in TEM images.(5) Steps on Si (111) have lattice strain parallel to the surface. This may be partly due to surface reconstruction.In the present reseach project we designed and constructed a electron microscope specimen holder by which we can apply strain on surfaces. It was found that Si specimen can be heated in-situ in the microsocpe up-to 1200ﾟC and surface strain of about 0.1% can be applied.With use of this holder, we could observe that Si (001) 2x1 domains domainate on the surface under a compressive strain and 1x2 domains dominate under a delatational strain. It was previously reported that a step up current causes major domains of 2x1 on Si (001) surface. However, it was found that current effect is weaker than the strain effect. Less

超高真空条件下的透射电子显微镜（TEM）可以揭示表面结构和表面动态过程。该技术的特点之一是它可以表征由于表面重建而产生的表面内表面应力。大多数表面重构和吸附质结构，如果没有基底，并不总是与下面的基底晶格具有相同的晶格周期。这是内表面应力的来源。这会导致晶体薄膜弯曲。相反，在弯曲晶体表面结构或表面结构领域有利于这种应变指定。在前一种情况下，即使在强内应力的情况下，多域形成也不会引起弯曲。 TEM 可以看到内表面应力引起的晶格应变。我们的观察结果总结如下。(1) Si (111) 4x1-In 结构没有内应力。(2) Si (001) 2x1 表面是各向异性应力。(3) Si(111) 7x7 结构处于滑移应力下，7x7 和 1x1 结构之间的相界有很强的晶格应变。(4) Si (111) 5x2-Au表面具有各向异性晶格应力。 5x2结构的域边界在TEM图像中具有强烈的应变对比。(5)Si(111)上的台阶具有平行于表面的晶格应变。这可能部分归因于表面重建。在目前的研究项目中，我们设计并构造了一个电子显微镜样品架，通过它我们可以在表面上施加应变。研究发现，Si 样品可以在显微镜中原位加热至 1200°C，并且可以施加约 0.1% 的表面应变。通过使用该支架，我们可以观察到在压缩应变下，Si (001) 2x1 域在表面上形成域，而在拉伸应变下，1x2 域占主导地位。之前有报道称，升压电流会在 Si (001) 表面上产生 2x1 的主畴。然而，人们发现电流效应弱于应变效应。较少的

项目成果

H.Minoda.K.Yagi: "REW Studies of Ge Growth on Au Adsorbed Si(001) Surfaces" Surface Science. (in press). (1995)

H.Minoda.K.Yagi：“金吸附 Si(001) 表面上 Ge 生长的 REW 研究”表面科学。

T.Senoh, H.Minoda K.Yagi: "Indirect Heating Specimen Holder for REM Studies of Current Effects on Si Surfaces" Proc.ICEM. 13 2B. 1029-1030 (1994)

T.Senoh、H.Minoda K.Yagi：“用于硅表面电流效应 REM 研究的间接加热样品架”Proc.ICEM。

T.Senoh,H.Minoda,K.Yagi: "Indirect Heating Specimen Holder for REM Studies of Current Effects on Si Surfaces" Proc.ICEM 13. 213. 1029-1030 (1994)

T.Senoh、H.Minoda、K.Yagi：“用于硅表面电流效应 REM 研究的间接加热样品架” Proc.ICEM 13. 213. 1029-1030 (1994)

T.Suzuki,Y.Tanishiro,H.Minoda,K.Yagi,M.Suzuki: "REM Observations of Si(hhk) Surfaces and Their Vicinal Surfaces" Surface Sci. 298. 473-477 (1993)

T.Suzuki、Y.Tanishiro、H.Minoda、K.Yagi、M.Suzuki：“Si(hhk) 表面及其邻近表面的 REM 观察”表面科学。

H.Yamaguchi and K.Yagi: "Current Effects on Si(111) Surfaces at the Phase Transition between the 7x7 and the 1x1 Structures" Surface Sci.287/288. 820-825 (1993)

H.Yamaguchi 和 K.Yagi：“7x7 和 1x1 结构之间相变时对 Si(111) 表面的电流影响”Surface Sci.287/288。