Origin of enhanced Ge interdiffusion at the initial stage of Ge deposition on Si(5 5 12)-2 ¡Á 1: Tensile stress induced by substrate chain structures

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• 作者：Hidong Kim ; Otgonbayar Dugerjav ; Ganbat Duvjir ; Huiting Li ; Jae M. Seo ; ^{seojm@jbnu.ac.kr}
• 关键词：Semiconductor&ndash ; semiconductor interfaces ; Diffusion and migration ; Silicon ; Germanium ; High index single crystal surfaces ; Surface structure ; morphology ; roughness ; and topography ; Scanning tunnelling microscopy ; Photoelectronspectroscopy
• 刊名：Surface Science
• 出版年：2012
• 出版时间：April, 2012
• 年：2012
• 卷：606
• 期：7-8
• 页码：744-748
• 全文大小：819 K

文摘

By combined investigation of STM and synchrotron PES on Ge/Si(5 5 12)-2 ¡Á 1 at 530 ¡ãC, it has been found that, in addition to the upward-relaxed surface Si atoms, a subsurface Si atom is also readily replaced by an arriving Ge atom at the initial adsorption stage. Such enhanced interdiffusion is due to a unique character of one-dimensional chain structures of the reconstructed substrate, such as <em>¦Ðem>-bonded and honeycomb chains not existing on other low-index Si surfaces such as Si(001)-<em>cem>(4 ¡Á 2) and Si(111)-7 ¡Á 7, applying a tensile surface stress to the neighbouring subsurface atoms. Interdiffusion of Ge having lower surface energy induces adsorption of the displaced Si atoms on the surface to form sawtooth-like facets composed of (113)/(335) and (113)/(112) with arriving Ge atoms until the surface is filled with those facets. Such displacive adsorption is the origin of high Si concentration of formed facets.