Optically Probing the Chemistry of Thin Film Processes

该项目的目标是通过获得在薄膜过程中发生在表面的化学物质的详细视图来确定等离子体辅助化学蚀刻电子材料的化学步骤。方法是使用已经开发的表面光学探头，根据需要开发和使用新的表面敏感光学探头，并利用现有的诊断技术来探测等离子体。几个关键材料的蚀刻，包括Si， GaN和SiC，将在几种环境下进行研究，包括C12和C12/Ar高电荷密度等离子体，以了解有助于这些材料过程的分子和表面过程。激光诱导热脱附（LITD）是一种表面敏感的光学探针，将用于研究电感耦合等离子体（ICP）中蚀刻过程中形成的稳态面层，电感耦合等离子体是一种突出的高电荷密度等离子体。这一层有时只有一层厚，其形成和解吸的化学性质被认为是理解蚀刻过程的关键。基于激光解吸的方法将用于原位和实时探测等离子体刻蚀。如果可能，激光诱导荧光（LIF）将用于检查解吸产物。当LIF检测不可能或不可行时，将监测激光解吸后等离子体诱导发射（PIE）的瞬态增加，以检测解吸产物。这种LD-PIE方法将作为拟议工作的一部分加以发展。初步研究表明，LD-PIE分析具有亚单层灵敏度。其他诊断方法将用于描述等离子体和蚀刻过程，如光学发射光度测定法、朗缪尔探测法和微波干涉测量法。该项目涉及具有高潜在技术相关性的材料科学主题领域的基础研究问题。该研究将为电子/光子器件的重要制造方面提供基础材料科学知识。现在有了新的实验光学工具，可以更详细地观察基本的表面过程，如果更好地理解这些过程，就可以促进基础科学和技术的进步。从研究中获得的基本知识和理解有望有助于提高先进器件和电路的性能和稳定性。该计划的一个重要特点是通过在基础和技术重要领域培养学生，将研究和教育相结合

The goal of this project is to identify the chemical steps in plasma-assisted chemical etching of electronic materials by obtaining a detailed view of the chemistry that occurs on the surface during this thin film process. The approach is to use optical probes of the surface, those that have been developed, and by developing and employing new surface-sensitive optical probes as needed, and by utilizing existing diagnostic techniques to probe the plasma. The etching of several key materials, including Si, GaN, and SiC, will be studied in several environments, including C12 and C12/Ar high charge density plasmas, to understand the molecular and surface processes that contribute to these materials processes. Laser-induced thermal desorption (LITD), a surface sensitive optical probe, will be used to study the steady-state surface layer that is formed during etching in an inductively coupled plasma (ICP), a prominent type of high charge density plasma. The chemistry of the formation and desorption of this layer, which is sometimes only a monolayer thick is considered key to understanding the etching process. Laser-desorption based methods will be used to probe in situ and in real time the plasma etching. When possible, laser induced fluorescence (LIF) will be used to examine the desorbed products. When LIF detection is not possible or feasible, the transient increase in plasma-induced emission (PIE) after laser desorption will be monitored to detect desorbed products. This LD-PIE method will be developed as part of the proposed work. Preliminary studies have shown that LD-PIE analysis can have submonolayer sensitivity. Other diagnostics will be used to characterize the plasma and the etching process, such as optical emission actinometry, Langmuir probing, and microwave interferometry.%%%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 important fabrication aspects of electronic/photonic devices. New experimental optical tools are now available to allow more detailed observation of elementary surface processes which when better understood allow advances in fundamental science and technology. The basic knowledge and understanding gained from the research is expected to contribute to improving the perform-ance and stability of advanced devices and circuits. 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.***