MRI/RUI: High Sensitivity Profiling of Hydrogen and Nitrogen Using Nuclear Reaction Analysis

该主要研究仪器RUI奖用于开发和建造基于亚拉巴马A M符合方案的改进型核反应分析（NRA）探测系统，但信噪比提高了一到两个数量级。以前的结果表明，通过修改检测器的几何形状和材料，更大，更有效的检测器是可能的，而不增加背景信号。通过使用样品冷却和光束光栅，这种更大的探测器将能够常规地分析半导体中的氢，灵敏度为百万分之一，表面深度分辨率为5纳米，同时与现有的IBA设施要求保持兼容。这种探测器的开发可能会增加NRA在材料表征领域的使用，因为它可以很容易地以最低的成本添加到任何现有的IBA设施中。这将允许公司和大学通过NRA进行氢分析，并使用NRA校准其他IBA技术，包括西姆斯。最后，该探测器在不降低锗探测器效率的情况下显著减少所有背景源（包括竞争性核反应）的能力应该为分析其他轻元素（包括氮、硼和碳）开辟新的机会，同时大大提高灵敏度。许多类型的材料的化学和机械性能，即使是微量的。NRA是一种功能强大的离子束技术，用于定量分析材料中的轻杂质，具有出色的深度分辨率。NRA以前曾被用于分析各种微量元素，包括H、B、C、N和F，用于从金属的氢脆到箭头的定年等问题。NRA的潜在重要应用包括使用氢或氮的SiO2/SiC和SiO2/Si界面的钝化研究以及金属中碳和硼的分布以测试计算机模拟的预测。目前，由于获得高灵敏度的固有技术困难，很少有电子公司或大学具有NRA能力。

This Major Research Instrumentation RUI award is for the development and construction of an improved Nuclear Reaction Analysis (NRA) detection system based upon the Alabama A&M coincidence scheme, but with one to two orders of magnitude improvement in the signal-to-noise ratio. Previous results indicate that by modifying the detector geometry and materials, a larger, more efficient detector is possible without increasing the background signal. By using sample cooling and beam rastering, this larger detector will be able to routinely profile hydrogen in semiconductors with a sensitivity of one part-per-million and a surface depth resolution of five nanometers while remaining compatible with existing IBA facility requirements. The development of this detector would likely increase the use of NRA in the materials characterization community since it could be easily added to any existing IBA facility with minimal cost. This would allow companies and universities to perform hydrogen profiling by NRA and to use NRA for calibrating other IBA techniques including SIMS. Finally, the detector's ability to dramatically reduce all background sources including competing nuclear reactions without the reduction in efficiency of a germanium detector should open up new opportunities for profiling other light elements including nitrogen, boron, and carbon with greatly improved sensitivities.Light trace elements are known to have dramatic effects on the electrical, chemical and mechanical properties of many types of materials in even minute quantities. NRA is a powerful ion beam technique for quantitatively profiling light impurities in materials with excellent depth resolution. NRA has previously been used to profile a wide range of trace elements including H, B, C, N, and F in problems ranging from hydrogen embrittlement of metals to the dating of arrowheads. Potentially important applications of NRA include passivation studies of SiO2/SiC and SiO2/Si interfaces using hydrogen or nitrogen and the profiling of carbon and boron in metals to test predictions of computer simulations. Presently, few electronic companies or universities have NRA capability due to the technical difficulties inherent in obtaining high sensitivity.