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

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 careers 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.