Crystallographic Disorder in Surfaces and Thin Films

表面和薄膜的晶体无序

• 批准号: 9304912
• 负责人: Max Lagally
• 金额: $ 78万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-09-01 至 1999-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9304912&HistoricalAwards=false
• 关键词: Crystallographic; Disorder; Surfaces; Thin; Films

9304912 Lagally The proposed effort aims to combine scanning tunneling microscopy (STM) with diffraction techniques to investigate diffusion, interactions with steps, initial film formation, and a number of other aspects of the kinetics and thermodynamics of film formation. Measurements are planned both in real time and in a quench-and-look mode. Epitaxial, Stranski-Krastanov, and Volmer-Weber systems will be investigated. From a combination of theoretical and experimental effort, quantitative values of energies, barriers, and rates will be extracted. Systems include Si, Ge, and a number of metals on SI(001) substrates. Stress effects will be investigated using also Si whiskers as substrates. Because in STM measurements the electric field from the tip may influence rates of kinetic mechanisms, a comprehensive investigation of this phenomenon will be undertaken. %%% In this research diffraction methods and scanning tunneling microscopy are used to investigate atomic scale mechanisms involved in film growth. These mechansisms all have some sort of morphological or microstructural consequence. An analysis of the changing morphology can be interpreted in terms of the responsible mechanisms. There are in principle two ways of doing this: 1) real-time measurements or 2) quench-and-look measurements. In the former, one attempts to follow the changing positions of atoms or the shape and size of particular structures. The latter is effectively a series of snapshots of the morphologies that are frozen in at different times. The proposed work is important because crystal growth is at the basis of all thin-film technology. ***

9304912 Lagally提出的努力旨在将扫描隧道显微镜（STM）与衍射技术结合起来研究扩散，与步骤的相互作用，初始膜形成以及膜形成动力学和热力学的许多其他方面。测量计划在实时和在淬火和观察模式。外延，stranski - krstanov和Volmer-Weber系统将被研究。结合理论和实验的努力，将提取出能量、势垒和速率的定量值。系统包括Si， Ge和Si（001）衬底上的一些金属。应力效应也将使用硅晶须作为衬底进行研究。由于在STM测量中，来自尖端的电场可能会影响动力学机制的速率，因此将对这一现象进行全面的研究。在这项研究中，使用衍射方法和扫描隧道显微镜来研究薄膜生长的原子尺度机制。这些机制都有某种形态或微观结构的结果。对形态变化的分析可以从负责机制的角度来解释。原则上有两种方法：1)实时测量或2)淬火-观察测量。在前者中，人们试图跟踪原子位置的变化或特定结构的形状和大小。后者实际上是在不同时间冻结的形态的一系列快照。这项工作很重要，因为晶体生长是所有薄膜技术的基础。＊＊＊