NER: Nanoscale Electron Beam Stimulated Processing

该项目是对NSF 01-157类纳米科学与工程倡议的响应。该项目将探索电子刺激沉积和刻蚀作为选择性沉积和刻蚀纳米特征的替代技术。电子束促进生长和刻蚀过程的机理和反应动力学将使用标准的前驱体材料来阐明。将进行束流能量和电流密度测量，并对近表面区域的能量流进行模拟，以确定热焦耳加热对前体分子电子解离的贡献。将研究气相电子散射、样品充电和二次电子发射的影响，以了解这种纳米级过程可以实现的最小像素尺寸。该项目是田纳西大学(菲利普·D·拉克和大卫·C·喜悦)和北卡罗来纳州立大学(菲利普·罗素)的科学家合作的成果，将利用聚焦电子束研究纳米材料的操纵。在纳米尺度上操纵材料的能力对正在发生的纳米技术革命至关重要。要智能地设计和或修复纳米级设备，需要有选择地在纳米范围内以可控的方式存储和移除材料的技术。目前选择性沉积或刻蚀微观特征的技术包括离子束沉积和刻蚀，使用远场和近场光学的激光烧蚀刻蚀，以及使用精细微尖的机械磨损。在这些技术中，聚焦离子束技术可能是已扩展到纳米级的最成熟的技术。当使用离子束刺激沉积或刻蚀过程时，镓离子被注入到衬底中，这可以显著改变衬底的光学、电学或机械性能。离子-固体相互作用所固有的电荷也会引起邻近效应，还可能导致所谓的“河床效应”，当重离子束被散射时，河床效应会侵蚀附近的地物，并导致溅射。电子束激发沉积和刻蚀在概念上类似于现有的聚焦离子束方法，已被证明是一种可行的沉积纳米材料的技术。与离子束相比，使用电子束的主要优点是减少了污染和更小的光斑尺寸。

This project was received in response to Nanoscale Science and Engineering initiative, NSF 01-157, category NER. The project will explore electron stimulated deposition and etching as a alternative technique to selectively deposit and etch nanoscopic features. The mechanisms and reaction kinetics for the electron beam stimulated growth and etch processes will be elucidated using standard precursor materials. Beam energy and current density measurements will be performed and the energy flow will be modeled at the near surface region to determine the contribution of thermal Joule heating versus electron dissociation of the precursor molecules. The effect of gas phase electron scattering, specimen charging, and secondary electron emission will be investigated to understand the minimum pixel size that can be realized for this nanoscale process.This project is a collaborative effort between scientists at the University of Tennessee (Philip D. Rack and David C. Joy) and North Carolina State University (Phillip Russell) and will investigate nanoscale materials manipulation with focused electron beams. The ability to manipulate materials at the nanoscale is critical for the nanotechnology revolution that is occurring. To intelligently design and or repair nanoscale devices requires techniques to selectively and nanoscopically deposit and remove material in a controllable fashion. Current techniques to selectively deposit or etch microscopic features utilize ion beam deposition and etching, laser ablative etching using far field and near field optics, and mechanical abrasion using a fine microtip. Of these techniques, focused ion beam techniques are probably the most mature technology that has been extended into the nanoscale. When using an ion beam to stimulate a deposition or etch process, the gallium ions get implanted into the substrate, which can significantly change the optical, electrical, or mechanical properties of the substrate. Charging inherent to the ion-solid interaction also causes proximity effects and can also lead to so-called "riverbed effects" which erodes nearby features when the heavy ion beam is scattered and induces sputtering. Electron beam stimulated deposition and etching is conceptually similar to the existing focused ion beam approach and has been shown to be a viable technique for depositing nanoscopic materials. The main advantages of using an electron beams versus ion beams are reduced contamination and smaller spot sizes.