Multiscale Simulation of Laser Processing and Ablation of Semiconductor Materials

半导体材料激光加工和烧蚀的多尺度模拟

• 批准号: 0809015
• 负责人: Patrick Schelling
• 金额: $ 15万
• 依托单位: The University of Central Florida Board of Trustees
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-15 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0809015&HistoricalAwards=false
• 关键词: Multiscale; Simulation; Laser; Processing; Ablation

TECHNICAL SUMMARY:This award support research and education in optical interactions of lasers and semiconductor materials. This award is jointly supported by Chemical, Bioengineering, Environmental, and Transport Systems in the Division of Engineering and the Division of Materials Research. Research investigates how materials interact with lasers under conditions relevant to laser processing of covalent semiconductors. The work develops methods for predicting how processing conditions affect the resulting material structure. The work includes the development and use of novel computer simulation methods to elucidate the fundamental physical processes relevant to laser processing of covalent semiconductors. The general approach applies to intense femto-second pulses interacting with silicon. The researchers address the fundamental technical challenges relevant to the development of a multiscale model of heat and mass transport appropriate for far-from-equilibrium conditions. Electronic heat transport is treated at the continuum level, while the lattice dynamics are treated using classical molecular-dynamics. A crucial component of the proposed work is that the interatomic interactions will depend on the local electronic temperature TE. Parameters in the interactions will be based on a new modification of the popular Tersoff potential, with the dependence of the parameters on TE established by fitting to a large database of energies from finite-temperature ab initio calculations. This novel approach will capture nonthermal effects known to be important for sub-picosecond melting. Heat transport by excited charge carriers is addressed using ab initio simulations of excited liquids and the Kubo-Greenwood method. The coupling between the continuum description of the electrons and the lattice will be driven using Langevin dynamics with the damping parameter fit to experiment. The focus of the proposed work develops a model for silicon as a test case. The model will be tested in its treatment of the fundamental physics of laser ablation of crystalline silicon and laser annealing of amorphous silicon. Comparison to experiment is used to validate the results of the model, and produce new insight into the role of bond-weakening and ultrafast non-thermal processes to melting and ablation.Carrying out this project requires researchers to address the fundamental technical challenges relevant to the development of a multiscale model of heat and mass transport appropriate for far-from-equilibrium conditions. The effort includes both scientific and educational elements. The theoretical and computer simulation methods will expand researchers' ability to model the fundamental physics of laser ablation and will be applied to the technologically relevant processes for crystalline silicon and laser annealing of amorphous silicon. The work as educational value in developing student skills, particularly the graduates and undergraduates who are directly involved in the research and the activities aid in recruiting new students for graduate study in materials simulation. The researchers and students engage in workshop activities that introduce students to materials simulation, including molecular-dynamics simulation and visualization which is coordinated with the Florida Society for Materials Simulation. The work integrates education and research through the development of course in materials simulation.NONTECHNICAL SUMMARY:This award support research and education in optical interactions of lasers and semiconductor materials. Research investigates how materials interact with intense lasers beams under conditions relevant to laser processing of semiconductors. The work develops methods for predicting how processing conditions affect the resulting material structure. The work includes the development and use of novel computer simulation methods to elucidate the fundamental physical processes relevant to laser processing of covalent semiconductors. The general approach applies to intense ultrafast laser pulses interacting with silicon. In carrying out this project, researchers will address the fundamental technical challenges relevant to the development of a multiscale model of heat and mass transport appropriate for far-from-equilibrium conditions. The effort includes both scientific and educational elements. The theoretical and computer simulation methods will expand researchers' ability to model the fundamental physics of laser ablation and will be applied to the technologically relevant processes for laser etching of silicon. The work as educational value in developing student skills, particularly the graduates and undergraduates who are directly involved in the research and the activities aid in recruiting new students for graduate study in materials simulation. The researchers and students engage in workshop activities that introduce students to materials simulation, including computer simulation and visualization which is coordinated with the Florida Society for Materials Simulation. The work integrates education and research through the development of course in materials simulation.

该奖项支持激光和半导体材料的光学相互作用的研究和教育。该奖项由工程部和材料研究部的化学，生物工程，环境和运输系统共同支持。 研究调查了材料如何在与共价半导体激光加工相关的条件下与激光相互作用。这项工作开发了预测加工条件如何影响所得材料结构的方法。这项工作包括开发和使用新的计算机模拟方法来阐明与共价半导体激光加工相关的基本物理过程。一般的方法适用于强烈的飞秒脉冲与硅相互作用。研究人员解决了与开发适用于远离平衡条件的热量和质量传输的多尺度模型相关的基本技术挑战。 电子的热输运是在连续水平上处理，而晶格动力学处理使用经典的分子动力学。所提出的工作的一个关键组成部分是，原子间的相互作用将取决于当地的电子温度TE。相互作用中的参数将基于流行的Tersoff势的新修改，通过拟合到来自有限温度从头计算的能量的大型数据库来建立参数对TE的依赖性。这种新的方法将捕获已知对亚皮秒熔化很重要的非热效应。热输运的激发载流子是解决使用从头计算模拟激发液体和Kubo-Greenwood方法。 电子的连续描述和晶格之间的耦合将使用Langevin动力学与实验拟合的阻尼参数来驱动。所提出的工作的重点是开发一个硅模型作为测试用例。该模型将在晶体硅的激光烧蚀和非晶硅的激光退火的基本物理的治疗进行测试。与实验的比较是用来验证模型的结果，并产生新的洞察键弱化和超快非热过程的作用熔化和ablation.Carrying这个项目需要研究人员解决的基本技术挑战的发展的多尺度模型的热量和质量输运适合远离平衡条件。这项工作包括科学和教育两方面的内容。理论和计算机模拟方法将扩大研究人员对激光烧蚀基本物理模型的能力，并将应用于技术相关过程， 晶体硅和非晶硅的激光退火。这项工作在培养学生技能方面具有教育价值，特别是直接参与研究和活动的研究生和本科生，有助于招收新学生进行材料模拟研究生学习。研究人员和学生参加研讨会活动，向学生介绍材料模拟，包括分子动力学模拟和可视化，这是与佛罗里达材料模拟学会协调。通过材料模拟课程的开发，将教育和研究结合起来。非技术概要：该奖项支持激光和半导体材料的光学相互作用的研究和教育。 研究调查了材料如何在与半导体激光加工相关的条件下与强激光束相互作用。这项工作开发了预测加工条件如何影响所得材料结构的方法。这项工作包括开发和使用新的计算机模拟方法来阐明与共价半导体激光加工相关的基本物理过程。一般的方法适用于强烈的超快激光脉冲与硅相互作用。在执行该项目时，研究人员将解决与开发适用于远离平衡条件的热量和质量传输多尺度模型相关的基本技术挑战。这项工作包括科学和教育两方面的内容。理论和计算机模拟方法将扩大研究人员对激光烧蚀基本物理建模的能力，并将应用于硅激光蚀刻的技术相关工艺。这项工作在培养学生技能方面具有教育价值，特别是直接参与研究和活动的研究生和本科生，有助于招收新学生进行材料模拟研究生学习。研究人员和学生参加研讨会活动，向学生介绍材料模拟，包括计算机模拟和可视化，这是与佛罗里达材料模拟学会协调。这项工作通过材料模拟课程的开发整合了教育和研究。