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

9632252 Cahill本研究项目旨在使用原子分辨率STM和分子动力学（MD）计算机模拟方法对离子引起的表面损伤进行基本了解。 该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;该研究还面向严格测试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，理论上不能用二元碰撞近似来处理。 集体行为，如热尖峰在确定缺陷结构中起着至关重要的作用，并越来越重要的精密离子束处理应用，如浅注入掺杂的半导体。 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检查使用Ga、In和Au在1 keV至40 keV的能量范围内的离子撞击。 MD模拟将进行5-15 keV的影响，锗，铂，和非晶铜，以阐明表面损伤的机制。该研究将为先进的电子材料加工提供广泛技术相关的基础材料科学知识。 此外，从该研究项目中获得的知识和理解预计将通过提供基本理解和设计和处理更先进的材料和器件的基础，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在一个基本和技术上重要的领域对学生进行培训来整合研究和教育。***

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. ***