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项目的支持下，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，用于在接近5纳米的尺度上进行3D分子分析。这项研究有望产生新的仪器，为半导体器件生产中使用的薄膜的分子组织提供见解。这些见解可能会导致新的材料设计，确保向高性能计算设备的持续发展。Eller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民族参与科学、技术、工程和数学（STEM），并为学生提供与工业化学家互动和建立网络的机会。加州州立大学北岭分校的Eller小组将设计并验证一种实验方法，该方法可以跟踪3D纳米空间中的分子关联。将追求两个相互补充的目标；(i)在接近5纳米的尺度上横向阐明分子组织，（ii）也在垂直5纳米深度上阐明分子组织。分析方法是基于二次离子质谱（SIMS）的一种变体，称为纳米抛射SIMS，其中不使用聚焦离子束，而是使用一组（10^6 - 10^7）在空间和时间上分离的纳米抛射随机分析表面。这些弹丸的每一个样品都有一个纳米体积（直径约10纳米），电离后的喷射物被收集起来，进行质量分析，并作为一个单独的质谱储存起来。提出的研究的总体假设是分析物特异性二次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发射二次离子的轴向和径向能量，将提供它们在低于陨石坑大小的尺度上的横向组织信息。将这种新功能与低能氩簇深度剖面相结合，将能够在三个纳米尺度上分析分子均匀性。这种新仪器将允许发现SIMS过程中的基本机制，并为半导体器件生产中使用的薄膜均匀性提供更好的见解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.