Bhatta Umananda M, Dash J K, Roy Anupam, Rath A, Satyam P V
Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005, India.
J Phys Condens Matter. 2009 May 20;21(20):205403. doi: 10.1088/0953-8984/21/20/205403. Epub 2009 Apr 24.
Thin Au films (∼2 nm) were deposited on an Si(110) substrate epitaxially under ultra-high vacuum (UHV) conditions in a molecular beam epitaxy (MBE) system. Real-time in situ transmission electron microscopy (TEM) measurements were carried out at various temperatures (from room temperature to 700 °C), which shows the formation and growth of aligned gold silicide nanorod-like structures. The real-time selected-area electron diffraction patterns show the presence of silicon and unreacted gold at lower temperatures (up to 363 °C), while at higher temperatures only the signature of silicon has been observed. The diffraction analysis from room temperature cooled systems show the presence of gold silicide structures. Around 700 °C, 97% of the nanostructures were found to be aligned nanosilicide-rod-like structures with a longer side of ≈37 nm and aspect ratio of 1.38. For a high temperature annealed system (at 600 °C), selected-area diffraction (SAD) and high resolution lattice (after cooling down to room temperature) confirmed the formation of nano- Au(5)Si(2) structures. The alignment of gold silicide structures has been explained on the basis of lattice matching between the substrate silicon and silicide structures.
在分子束外延（MBE）系统的超高真空（UHV）条件下，将约2纳米厚的金薄膜外延沉积在Si(110)衬底上。在不同温度（从室温到700°C）下进行了实时原位透射电子显微镜（TEM）测量，结果显示了取向的硅化金纳米棒状结构的形成和生长。实时选区电子衍射图案表明，在较低温度（高达363°C）下存在硅和未反应的金，而在较高温度下仅观察到硅的特征。对室温冷却系统的衍射分析表明存在硅化金结构。在700°C左右，发现97%的纳米结构是取向的纳米硅化物棒状结构，长边约为37纳米，纵横比为1.38。对于高温退火系统（在600°C），选区衍射（SAD）和高分辨率晶格（冷却至室温后）证实形成了纳米Au(5)Si(2)结构。基于衬底硅和硅化物结构之间的晶格匹配，解释了硅化金结构的取向。
