Evolution of Stress and Mass Transport During keV Ion Bombardment

keV 离子轰击过程中应力和质量传递的演变

• 批准号: 0419840
• 负责人: David Cahill
• 金额: --
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0419840&HistoricalAwards=false
• 关键词: Evolution; Stress; Mass; Transport; During

This project seeks new knowledge and insight on fundamental features/mechanisms of ion beam materials processing, analysis and thin film deposition. Greater understanding is particularly sought of stress-states produced by keV ion beams and the relaxation of those stresses through radiation-induced viscous flow and changes in surface morphology. Project goals include answers to questions such as: Does radiation enhanced surface diffusion play a significant role in mass transport during low energy ion bombardment or is radiation-induced viscosity in the bulk of the near surface region a better description? Do low mass ions have the same radiation-induced viscosity as heavy ions despite large differences in the energy density of the cascade? (Computational results suggest that, when scaled properly, radiation-induced viscosity should be almost independent of material, ion energy and ion mass.) Does the proximity of grain boundaries or surfaces strongly modify radiation-induced viscosity? Are a series of spatially and temporally localized melting events equivalent to a very short but uniform melting? The approach encompasses experimental measurements of the evolution of stress created by keV ion bombardment of amorphous, nanocrystalline, and polycrystalline metals, ceramics, and semiconductors. Most films will be deposited in-situ and studies will include ion energy and temperature dependence of stress evolution; time dependence of stress generated by a time-varying ion flux; and stress evolution during de-wetting of films patterned by electron beam lithography. Experiments will be complemented by computational studies of stress generation and relaxation in amorphous, nanocrystalline, and single-crystal materials.%%%The project addresses basic research issues in a topical area of materials science having high potential technological relevance. The research will contribute basic materials science knowledge at a fundamental level to new understanding and capabilities in electronic devices. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area. This project will support the education and training of two graduate research assistants. Additionally, undergraduate students will be incorporated into the research activities. New knowledge gained in the research will be integrated into graduate-level courses on surface physics and nanoscience. The PIs will work closely with engineers at APL Engineered Materials, an Urbana, IL company developing products for ion-beam assisted film deposition and a real-time stress sensor suitable for industry.***

该项目寻求有关离子束材料加工、分析和薄膜沉积的基本特征/机制的新知识和见解。人们特别寻求对 keV 离子束产生的应力状态以及通过辐射引起的粘性流和表面形态变化来松弛这些应力的更多了解。项目目标包括回答以下问题：辐射增强的表面扩散是否在低能离子轰击期间的质量传输中发挥重要作用，或者在近表面区域的大部分中辐射引起的粘度是否是更好的描述？尽管级联的能量密度存在很大差异，低质量离子是否具有与重离子相同的辐射诱导粘度？ （计算结果表明，当比例适当时，辐射引起的粘度应该几乎独立于材料、离子能量和离子质量。）晶界或表面的接近程度是否会强烈改变辐射引起的粘度？一系列空间和时间局部融化事件是否相当于非常短暂但均匀的融化？该方法包括对非晶、纳米晶和多晶金属、陶瓷和半导体的 keV 离子轰击所产生的应力演变进行实验测量。大多数薄膜将原位沉积，研究将包括离子能量和应力演化的温度依赖性；随时间变化的离子通量产生的应力的时间依赖性；以及电子束光刻图案化薄膜去湿过程中的应力演变。实验将通过非晶、纳米晶和单晶材料中应力产生和松弛的计算研究来补充。%%%该项目解决具有高度潜在技术相关性的材料科学主题领域的基础研究问题。该研究将从根本上为电子设备的新理解和能力贡献基础材料科学知识。该计划的一个重要特点是通过在基础和技术重要领域对学生进行培训，将研究和教育结合起来。该项目将支持两名研究生研究助理的教育和培训。此外，本科生将被纳入研究活动。研究中获得的新知识将被纳入表面物理和纳米科学的研究生课程中。 PI 将与 APL Engineering Materials 的工程师密切合作，该公司是伊利诺伊州厄巴纳市的一家公司，开发离子束辅助薄膜沉积产品和适合工业的实时应力传感器。***