A Combined Experimental and Theoretical Investigation of the Plasma-Surface Interactions in Plasma Deposition of Hydrogenated Amorphous and Nanocrystalline Silicon Films

氢化非晶硅和纳米晶硅薄膜等离子体沉积中等离子体-表面相互作用的实验与理论相结合的研究

• 批准号: 0078711
• 负责人: Eray Aydil
• 金额: $ 25.5万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-10-01 至 2003-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0078711&HistoricalAwards=false
• 关键词: Combined; Experimental; Theoretical; Investigation; Plasma

0078711AydilChemically reactive gas plasmas are used widely for etching and deposition of thin films and enable a whole class of technologies in the microelectronics industry. Despite the wide spread use and importance of such plasmas, optimization of plasma processes and design of plasma reactors rely heavily upon trial-and-error experimentation. There is a strong need for fundamental understanding of the intricate and complex coupling between plasma physics, homogeneous and heterogeneous chemistry, and species transport in plasma reactors. In particular, interactions of ions and radicals produced in chemically reactive gas plasmas with surfaces exposed to the discharge remain among the least understood aspects of plasma processing technologies. This lack of knowledge on surface reaction mechanisms and kinetics is a major limitation to the predictive capabilities of plasma reactor models that aim to integrate the plasma physics with gas phase and surface chemistry.A research strategy that integrates plasma and surface diagnostics with atomistic simulations is proposed to provide definitive conclusions about plasma-surface interactions during deposition of hydrogenated amorphous and nanocrystalline silicon films from SiH4/H2,/Ar glow discharges. Si film deposition is chosen as a prototypical chemical process because of its technological importance in the semiconductor industry. The proposed study aims at identifying the elementary surface chemical reactions that govern the plasma deposition mechanism, determining the corresponding reaction rates, and elucidating how these surface kinetic processes affect the evolution of the structure and composition of the surface. Such knowledge can only be achieved through synergistic analysis of the experimental and simulation results.To this end, atomic-scale computer simulations will be employed to study the interactions of silane molecular fragments, H atoms, and energetic ions from the plasma with the deposition surfaces. For detailed mechanistic study of plasma-surface interactions, molecular-dynamics, molecular-statics, and Monte Carlo simulators have been developed based on interatomic potential-energy functions, which have been tested exhaustively to assess their validity in comparison with ab initio calculations and experimental data. In addition, ab initio calculations within density functional theory will be used to generate accurate chemical reaction energy surfaces and variational rate theory will be employed to calculate the corresponding reaction rates. Furthermore, hybrid off-lattice kinetic Monte Carlo simulations will be implemented for full-scale dynamical modeling of the plasma deposition process over realistic time scales. These computational studies will identify surface chemical reactions that occur on surfaces exposed to a chemically reactive plasma, analyze quantitatively the energetics and kinetics of these reactions, and elucidate the elementary steps of the plasma deposition mechanism. The results of the computer simulations will be compared with experimental data and the insights gained from the simulations will be used to guide new experimental studies and design new plasma deposition strategies.In situ surface and plasma diagnostic methods will be used to study the phenomena occurring in the gas phase and on surfaces during film growth. Surface diagnostics will include in situ attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and in situ spectroscopic ellipsometry. ATR-FTIR will be at the heart of our experimental plan: The PI's have developed this technique in order to study surface physics and chemistry in a plasma environment. ATR-FTIR will be used to determine the growth surface composition as a function of the fluxes and energies of species incident onto the surface. The plasma gas-phase diagnostics will include various spectroscopic methods, such as infrared and visible emission spectroscopy, and line-of-sight threshold-ionization mass spectroscopy to detect and measure the radical energies and fluxes impinging on the surface.The proposed research is pioneering in linking experimental in situ plasma and surface diagnostics with atomic-scale dynamical modeling and theoretical surface reaction analysis to establish fundamental mechanistic and quantitative understanding of deposition surface interactions with chemically reactive plasmas and how this interactions evolve during the deposition process. In addition, the proposed research will set the stage for developing an accurate chemical reaction database that can be utilized for equipment-scale plasma reactor modeling. Undertaking such a challenging research effort is particularly timely given the recent experimental and theoretical advances in the field.The scientific underpinnings of plasma processing are multidisciplinary and cut across traditional boundaries between different disciplines including physics, chemistry, chemical and electrical engineering. Thus, the proposed fundamental study in plasma-surface interactions provides an ideal educational tool for training students and postdoctoral scholars in addressing technologically important research problems using an integrated experimental and theoretical approach.***

0078711化学反应性气体等离子体广泛用于薄膜的蚀刻和沉积，并在微电子工业中实现了一整类技术。 尽管这种等离子体的广泛使用和重要性，等离子体工艺的优化和等离子体反应器的设计严重依赖于试错实验。 有一个强烈的需要等离子体物理，均相和非均相化学，和物种传输等离子体反应器之间的复杂和复杂的耦合的基本理解。 特别地，在化学反应性气体等离子体中产生的离子和自由基与暴露于放电的表面的相互作用仍然是等离子体处理技术中最不了解的方面。 本文提出了一种将等离子体和表面诊断与原子模拟相结合的研究策略，以提供关于等离子体反应器的明确结论。SiH 4/H2，/Ar辉光放电沉积氢化非晶硅和纳米晶硅薄膜过程中的表面相互作用。 硅薄膜沉积被选为一个典型的化学工艺，因为它在半导体工业中的技术重要性。 拟议的研究旨在确定基本的表面化学反应，支配等离子体沉积机制，确定相应的反应速率，并阐明这些表面动力学过程如何影响表面的结构和组成的演变。 这些知识只能通过实验和模拟结果的协同分析来实现。为此，原子尺度的计算机模拟将被用来研究硅烷分子碎片、H原子和来自等离子体的高能离子与沉积表面的相互作用。 对于等离子体表面相互作用的详细机制研究，分子动力学，分子静力学和蒙特卡罗模拟器已经开发的基础上原子间的势能函数，已被彻底测试，以评估其有效性与从头计算和实验数据比较。 此外，密度泛函理论中的从头计算将用于生成准确的化学反应能量表面，变速率理论将用于计算相应的反应速率。 此外，混合非格子动力学蒙特卡罗模拟将实现在现实的时间尺度上的等离子体沉积过程的全尺寸动态建模。 这些计算研究将确定暴露于化学反应等离子体的表面上发生的表面化学反应，定量分析这些反应的能量学和动力学，并阐明等离子体沉积机制的基本步骤。 计算机模拟的结果将与实验数据进行比较，从模拟中获得的见解将用于指导新的实验研究和设计新的等离子体沉积策略。原位表面和等离子体诊断方法将用于研究薄膜生长过程中气相和表面上发生的现象。 表面诊断将包括原位衰减全反射傅里叶变换红外光谱法和原位椭圆偏振光谱法。 ATR-FTIR将是我们实验计划的核心：PI已经开发了这项技术，以研究等离子体环境中的表面物理和化学。 ATR-FTIR将用于确定生长表面组成，作为入射到表面上的物质的通量和能量的函数。 等离子体气相诊断将包括各种光谱方法，例如红外和可见光发射光谱，和视线阈值电离质谱检测和测量自由基的能量和通量撞击在表面上。拟议的研究是开创性的实验原位等离子体和表面诊断与原子，尺度动力学建模和理论表面反应分析，以建立沉积表面与化学反应等离子体相互作用的基本机理和定量理解，以及这种相互作用在沉积过程中如何演变过程 此外，拟议的研究将为开发一个准确的化学反应数据库，可用于设备规模的等离子体反应器建模奠定基础。 鉴于该领域最近的实验和理论进展，开展这样一项具有挑战性的研究工作是特别及时的。等离子体处理的科学基础是多学科的，跨越了不同学科之间的传统界限，包括物理，化学，化学和电气工程。 因此，拟议的等离子体表面相互作用的基础研究提供了一个理想的教育工具，用于培训学生和博士后学者使用综合实验和理论方法解决技术上重要的研究问题。