CAREER: Evaluating Molecular Homogeneity in Three Nanometric Dimensions Using Nano-Projectile Secondary Ion Mass Spectrometry

在化学系化学测量和成像计划的支持下，Michael Eller和他在加州州立大学北岭分校(CSUN)的学生将致力于开发新的分析方法，以执行接近5纳米规模的3D分子分析。预计这项研究将产生正在设计的新仪器，以深入了解半导体器件生产中使用的薄膜的分子结构。这些见解可能会导致新的材料设计，确保更高性能的计算设备继续取得进展。埃勒博士还将建立新的招聘和推广计划，以促进未被充分代表的少数族裔参与科学、技术、工程和数学(STEM)，并为学生提供与工业中的化学家互动和建立网络的机会。加州州立大学北岭分校的埃勒小组将设计并验证一种在3D纳米空间跟踪分子关联的实验方法。将追求两个相辅相成的目标：(I)在接近5纳米的尺度上横向阐明分子组织；(Ii)也在垂直方向上阐明5纳米的深度。这种分析方法是基于二次离子质谱仪(SIMS)的一种变体，称为纳米弹丸SIMS，其中不使用聚焦的离子束，而是用一套(10^6-10^7)空间上在时间上分开的纳米弹丸随机地分析表面。每一颗射弹的样品都是纳米体积(直径约10纳米)，电离抛射物被收集、质量分析并存储为单独的质谱图。拟议研究的总体假设是，分析物特定的次级离子携带与其原始分子组织相关的信息。通过空间分辨探测记录共同发射的二次离子的轴向和径向能量，将在撞击坑大小以下的尺度上提供关于它们横向组织的信息。将这一新能力与低能量Ar团簇深度剖析相结合，将能够在三个纳米维度上分析分子的同质性。这一新的仪器将允许发现SIMS过程中的基本机制，并提供对半导体设备生产中使用的薄膜的一致性的更深入的见解。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Michael Eller and his students at California State University Northridge (CSUN) will work on developing new analytical approaches for performing 3D molecular analysis at scales approaching five nanometers. The research is expected to result in new instrumentation that is being designed to provide insights into the molecular organization of thin films used in the production of semiconductor devices. These insights may lead to new material designs, ensuring continued progress towards higher performing computational devices. Dr. Eller will also establish new recruitment and outreach programs to promote participation of underrepresented minorities in science, technology, engineering and mathematics (STEM )and provide opportunities for students to interact and network with chemists working in industry.The Eller group at Cal-State-Northridge will devise and validate an experimental methodology that tracks molecular associations in 3D nanometric space. Two complementary objectives will be pursued; (i) elucidating molecular organization laterally on a scale approaching 5 nm and (ii) also vertically 5 nm in depth. The analytical approach is based on a variant of secondary ion mass spectrometry (SIMS) termed nanoprojectile SIMS, where instead of using a focused ion beam, a surface is analyzed stochastically with a suite (10^6 – 10^7) of nanoprojectiles separated in space in time. Each of these projectiles samples a nanovolume (~10 nm in diameter) and the ionized ejecta are collected, mass analyzed, and stored as an individual mass spectrum. The overall hypothesis of the proposed research is that analyte-specific secondary ions carry information related to their original molecular organization. Recording the axial and radial energies of co-emitted secondary ions via spatially resolved detection will provide information on their lateral organization at a scale below the size of the impact crater. Combining this new capability with low energy argon cluster depth profiling will enable analysis of the molecular homogeneity in three nanometric dimensions. This new instrumentation will allow for the discovery of fundamental mechanisms in the SIMS process and provide enhanced insights into the uniformity of thin films used in the production of semiconductor devices.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.