Low-Density Impinging Reactive Plasma Jets for Thin Film Synthesis

这项提议代表了斯坦福大学的马克·卡佩利和康奈尔大学的伊恩·博伊德合作研究项目的一半。PI计划研究流动的、低密度的、化学反应的等离子体，这些等离子体是由弧形膨胀到真空中产生的，用于材料合成。这项工作将包括实验和数值研究相结合。这项实验研究将在斯坦福大学进行，它将包括光学技术，如激光诱导荧光，以测量数字密度、温度和等离子体速度。本课程的目标是从机理上理解在等离子体条件下氮化硼和碳化硅的合成。实验研究中采用的方法是将含碳、硅和硼的反应物注入到低密度、超音速、反应性等离子体流中，并与温控表面相互作用，以沉积硬质陶瓷薄膜。激光诱导荧光和吸收光谱将被用来研究气体在等离子体中的流动和混合行为。物种的通量将通过分子束质谱学进行监测。沉积的薄膜将用X射线光电子能谱、扫描电子显微镜、红外和拉曼光谱进行表征。实验研究的主要目标是找出有利于合成C：BN或B-碳化硅的等离子体条件，而不是它们的六方同素异形体。另一个目标是提供以下方面的实验测量：等离子体流动特性(例如。温度、速度)、原子氢浓度、甲基自由基浓度和反应物种通量。

ABSTRACT CTS-9312892 CAPPELLI This proposal represents one half of a collaborative research program between Mark Cappelli at Stanford and Iain Boyd at Cornell. The PIs plan to study flowing, low density, chemically reacting plasmas generated by an arc expansion into vacuum for use in material synthesis. The effort will include a combined experimental and numerical investigation. The experimental investigation, which is the subject of this proposal, which will take place at Stanford, will include optical techniques such as laser induced fluorescence to measure number densities, temperatures and plasma velocities. The goal is to develop a mechanistic understanding of boron nitride and silicon carbide syntheses under plasma conditions. The approach to be taken in the experimental study is the injection of carbon, silicon and boron containing reactants into a low-density, supersonic, reactive plasma flow, and the interaction of this flow with a temperature controlled surface to deposit hard ceramic thin films. Laser induced fluorescence and absorption spectroscopy will be used to study the gasdynamic flow and mixing behavior in the plasma. Species fluxes will be monitored by molecular beam mass spectroscopy. Deposited films will be characterized using x-ray photoelectron spectroscopy, scanning electron microscopy and infrared and Raman spectroscopy. The primary objective of the experimental study is to identify plasma flow conditions that favor the synthesis of c:BN or b-SiC over their hexagonal allotropes. Another objective is to provide experimental measurements of: plasma flow properties (e.g.. temperature, velocity), atomic hydrogen concentrations, methyl radical concentrations, and reactive species fluxes.