Microscopy and Modeling of Collective Behavior during Ion Beam Processing of Materials

本研究项目旨在利用原子分辨率STM和分子动力学（MD）计算机模拟方法对离子诱导的表面损伤进行基本理解。方法是表征各种各样的材料，并将使用STM观察到的损伤与离子表面碰撞的MD模拟相关联；该研究还旨在批判性地测试MD模拟中常见的一些假设。固体中缺陷的产生是一个复杂的多体过程，在理论上不能用二元碰撞近似来处理。热峰值等集体行为在确定缺陷结构中起着至关重要的作用，并且在半导体浅植入掺杂等精密离子束加工应用中越来越重要。各种材料（Ge, Si, Au, Pt, Cu, Ni, GaAs， GaN和非晶NiZr）将通过MBE生长，并通过STM检测在1 keV至40 keV能量范围内使用Ga， In和Au的离子影响。将进行5-15 keV对Ge， Pt和非晶Cu的影响的MD模拟，以阐明表面损伤的机制。这项研究将在与先进电子材料加工广泛技术相关的基础水平上贡献基础材料科学知识。此外，从本研究项目中获得的知识和理解有望通过为设计和加工更先进的材料和器件提供基本的理解和基础，从而为提高先进器件和电路的性能做出贡献。该计划的一个重要特点是通过培养学生在一个基础和技术上重要的领域的研究和教育的整合。＊＊＊

9632252 Cahill This research project aims for fundamental understanding of ion-induced surface damage using atomic resolution STM and molecular dynamics(MD) computer simulation methods. The approach is to characterize a wide variety of materials and correlate the damage observed using the STM to MD simulations of the ion-surface collisions; the research is also oriented toward critically testing some of the assumptions commonly made in MD simulations. Defect generation in solids is a complex many-body process which cannot be theoretically treated in the binary collision approximation. Collective behaviors such as thermal spikes play a critical role in determining defect structures and are increasingly important for precision ion-beam processing applications such as shallow implant doping of semiconductors. A variety of materials(Ge, Si, Au, Pt, Cu, Ni, GaAs, GaN and amorphous NiZr) will be grown by MBE and examined by STM for ion impacts using Ga, In, and Au in the energy range of 1 keV to 40 keV. MD simulations will be performed for 5-15 keV impacts on Ge, Pt, and amorphous Cu to elucidate the mechanisms of surface damage. %%% The research will contribute basic materials science knowledge at a fundamental level of broad technological relevance to advanced electronic materials processing. Additionally, the knowledge and understanding gained from this research project is expected to contribute in a general way to improving the performance of advanced devices and circuits by providing a fundamental understanding and a basis for designing and processing more advanced materials and 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. ***