An Investigation of the Heterogeneous Chemistry Occurring between Atoms and Organometallics during Thin Film Synthesis

科林·A·沃尔登研究所：科罗拉多矿物学院建议编号：0626226标题：薄膜合成过程中原子和有机金属之间的非均相化学研究智能优点：该项目是一种被称为高真空等离子体辅助化学气相沉积(HVP-CVD)的薄膜合成的新方法。在HVP-CVD中，金属有机前驱体在无碰撞的条件下被传输到衬底，在那里它们在高通量的反应原子下反应。HVP-CVD的优势包括降低了衬底温度、显著的速率、固有的一致性、易于掺杂，以及能够利用与传统CVD/ALD技术不兼容的高真空诊断直接在现场研究这些工艺。金属有机化合物的非均相氧化和还原形成薄膜分别是通过与原子氧和原子氢的反应完成的。这项工作的一个目标是测量基本反应动力学，并通过比较不同类型的前体(即金属烷基、烷氧基、-二酮酸盐)来了解它们对金属和配体结构的依赖。将采用热化学计算、文献综述和实验筛选来加快对潜在前体的评估。有希望的候选人将接受一套现场诊断的详细检查。具体地说，高密度等离子体源的性能将使用原子通量的动态门控测量来量化和优化。将使用发射光谱和详细的建模来进一步了解等离子体源。用石英晶体微天平测量金属有机前驱体的吸附/脱附行为。这项工作的第二个目标是将HVP-CVD应用于薄膜结构的合成，以应对摩尔定律带来的严峻挑战。令人感兴趣的材料包括二氧化硅的高介电性替代品以及用来取代铝的金属互连结构。对沉积的薄膜的成分、结构和光电性能进行了表征。金属-绝缘体-半导体器件将被制造和测试，从而充分建立工艺-结构-性能-性能关系。广泛影响HVP-CVD可以通过适当选择试剂来合成氧化物、金属、氮化物和碳化物。它的优点也可以与微电子工艺兼容地应用，例如晶片清洗和接口工程。HVP-CVD是一种灵活的技术，有助于在纳米级实现这些应用。从某种意义上说，HVP-CVD是一种工程解决方案，它将CVD的控制权交还给合成化学家。因此，它为有助于纳米科学的薄膜和界面的分子设计和工程打开了无限的潜力。研究活动将以一种综合的方式为从一年级到博士生的学生创造新的教育机会。PI将指导来自代表性不足群体的学生，并试行一项新的联合理学士/理科硕士学位计划。后者将允许本科生利用他们的研究经验，并将其应用于论文硕士学位。此外，这项工作产生的材料将被整合到现有的半导体加工课程中。跨学科团队将使用高介电体来制造电容器和晶体管。这笔助学金还将补充正在进行的将计算流体力学整合到本科交通运输课程中的努力。

ABSTRACTPI: Colin A. Wolden Institution: Colorado School of MinesProposal Number: 0626226Title: An Investigation of the Heterogeneous Chemistry Occurring between Atoms and Organometallics during Thin Film SynthesisIntellectual Merit:This project is a novel approach to thin film synthesis that is described as high vacuum plasma-assisted chemical vapor deposition (HVP-CVD). In HVP-CVD organometallic precursors are transported to a substrate under collisionless conditions, where they react under a high flux of reactive atoms. Advantages of HVP-CVD include reduced substrate temperature, significant rates, inherent uniformity, facilitated doping, and the ability to directly study these processes in-situ with high vacuum diagnostics that are not compatible with conventional CVD/ALD technologies. The heterogeneous oxidation and reduction of organometallics to form thin films is accomplished through reactions with atomic oxygen and atomic hydrogen, respectively. One goal of this work is to measure the fundamental reaction kinetics, and understand their dependence on both metal and ligand structure by comparing classes of precursors (i.e. metal alkyls, alkoxides, -diketonates). Thermochemistry calculations, literature review, and experimental screening will be employed to expedite the evaluation of potential precursors. Promising candidates will be subjected to detailed examination using a suite of in situ diagnostics. Specifically, the performance of the high-density plasma source will be quantified and optimized using dynamically gated measurements of atom flux. Emission spectroscopy and detailed modeling will be used to further understand the plasma source. A quartz crystal microbalance will be used to measure the adsorption/desorption behavior of organometallic precursors. Mass spectrometry will be used to measure the products of these surface reactions.The second goal of this work is to apply HVP-CVD to the synthesis of film structures required to meet the imposing challenges posed by Moores law. Materials of interest include high dielectric alternatives to SiO2 as well as metal interconnect structures to replace aluminum. The composition, structure and optoelectronic properties of the deposited films will be characterized. Metal-insulator-semiconductor devices will be fabricated and tested, allowing the full establishment of process-structure-property-performance relationships.Broader ImpactsHVP-CVD may be envisioned for the synthesis of oxide, metals, nitrides, and carbides through appropriate choice of reagents. Its benefits may also be applied compatibly with microelectronic processes such as wafer cleaning and interface engineering. HVP-CVD is a flexible technology that would help enable the implementation of these applications at the nanoscale. In a sense, HVP-CVD is an engineering solution that returns control of CVD to the synthetic chemist. As such, it opens unbounded potential for the molecular design and engineering of thin films and interfaces that are instrumental to nanoscience.The research activities will create novel educational opportunities for students ranging from freshmen to PhD candidates in an integrated fashion. The PI will mentor students from underrepresented groups and pilot a new combined BS/MS degree program. The latter will allow undergraduates to capitalize on their research experience and apply it to a thesis masters degree. Furthermore, the materials produced by this work will be integrated into an existing semiconductor processing course. Interdisciplinary teams will employ high dielectrics to fabricate capacitors and transistors. This grant will also supplement ongoing efforts to integrate computational fluid dynamic across the undergraduate transport curriculum.