CAREER: Molecular Perspectives of Gas-Surface Reactions during Growth of Thin Film Nanostructures

0846923 Agarwal该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。智力优势：该职业建议整合了对薄膜生长的纳米级控制至关重要的气体表面动力学主题领域的研究和教育活动。研究项目的目标与科罗拉多矿业学院一致？(CSM)专注于地球资源，能源和先进材料。特别是，研究将集中在原子和分子层沉积（ALD/MLD）。这些沉积技术在自限制的气-固表面反应的交替循环中操作。最近，ALD已被用于许多应用中，由于其能够提供大面积基板上的纳米级控制的膜？的组成和厚度。迄今为止，ALD工艺的开发主要是经验性的，除了少数金属氧化物外，很少有全面的研究。虽然ALD在很大程度上限于无机材料，但MLD是一种用于存款有机膜的新兴技术。有必要发展的异质化学发生在ALD/MLD工艺的分子理解，使他们可以开发到最大的潜力。这两种工艺的内在相容性可用于形成先进的无机-有机杂化膜。在这个研究和教育项目中，ALD/MLD过程将采用基础科学方法进行研究。已经组装了最先进的表面和气相诊断的组合，包括原位表面红外光谱，X射线光电子能谱，石英晶体微量天平，光谱椭圆偏振法和四极质谱。这种方法的强大功能是通过PI证明？的最近研究的ALD的二氧化钛使用O3。该项目将阐明ALD/MLD合成金属氧化物，功能聚合物和先进金属薄膜的关键分子途径。关于金属氧化物的工作将集中在O3和O自由基的应用上，尽管它们成为工业过程的氧化剂，但很少受到关注。MLD研究将探讨两种新的策略，以克服有机薄膜合成面临的关键限制：（a）过程化学，不产生反应副产物，和（B）？智能组装？其中初始试剂产生被掩蔽的官能团，该官能团被第二试剂选择性地活化。金属的研究将集中在成核的关键问题上，钌作为模型化合物。PI将进一步整合这三个主题领域的见解，以设计分子支架，用于预功能化表面上的金属薄膜的高密度成核。变革方面：这项研究可能具有潜在的变革性，因为它将揭示ALD/MLD过程中发生的分子转变，这将最终导致薄膜生长的新策略。此外，该计划将解决ALD中最不了解的过程之一，即金属在不同表面上的初始成核。更广泛的影响：该项目的一个固有特点是强调教育及其与研究的结合。具体而言，将追求三个相互关联的教育目标：（a）开发和评估薄膜加工新的跨学科选修课程;（B）通过研究提供密切的指导和职业咨询;（c）参与旨在增加少数民族学生在本科一级的录取和保留的外联方案。该项目还涉及与荷兰埃因霍温理工大学的研究生交流计划，这将促进两所大学学生的知识和文化体验。该项目解决了材料科学领域的基础研究问题，这些问题在微电子学，光电子学和光电子学等各个领域具有高度的技术相关性。这项研究是独一无二的，因为它汇集了各种最先进的表面和气相诊断，通过ALD和MLD研究薄膜和纳米层压材料沉积过程中的气体表面动力学。一般的方法和诊断工具将有助于PI建立一个更广泛的计划，用于研究其他薄膜沉积过程中的界面现象，如等离子体增强CVD。研究的多学科性质包括物理，化学，工程和材料科学。除了开发新的课程，这项工作的几个方面将用于加强现有的课程，在光电子学，等离子体科学和微细加工在CSM。

0846923Agarwal This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Intellectual Merit: This CAREER proposal integrates research and educational activities in the thematic area of gas-surface dynamics critical to nanoscale control of thin-film growth. The goals of the research program are aligned with the Colorado School of Mines? (CSM) focus on Earth resources, energy, and advanced materials. In particular, the study will concentrate on atomic and molecular layer deposition (ALD/MLD). These deposition techniques operate in alternating cycles of self-limiting, gas-solid surface reactions. Recently, ALD has been used in numerous applications due to its ability to deliver conformal films on large-area substrates with nanometer-scale control over the film?s composition and thickness. To date ALD process development has been largely empirical, and with the exception of a few metal oxides, there have been very few comprehensive studies. While ALD is largely limited to inorganic materials, MLD is an emerging technique to deposit organic films. There is a need to develop a molecular understanding of the heterogeneous chemistry that occurs in ALD/MLD processes, so that they may be developed to their fullest potential. The inherent compatibility of the two processes can be utilized for the formation of advanced inorganic-organic hybrid films. In this research and education project, ALD/MLD processes will be examined taking a fundamental science approach. A combination of state-of-the-art surface and gas-phase diagnostics has been assembled that include in situ surface infrared spectroscopy, x-ray photoelectron spectroscopy, quartz crystal microbalance, spectroscopic ellipsometry, and quadrupole mass spectrometry. The powerful capabilities of this approach are demonstrated through the PI?s recent studies on the ALD of TiO2 using O3. This project will illuminate the molecular pathways critical to ALD/MLD synthesis of metal oxides, functional polymers, and advanced metal films. Work on metal oxides will focus on the application of O3 and O radicals, which have received little attention despite becoming the oxidizers of choice for industrial processes. MLD studies will investigate two novel strategies to overcome key limitations facing organic thin film synthesis: (a) process chemistries that produce no reaction byproducts, and (b) ?smart assembly?, in which the initial reagent produces a masked functionality that is selectively activated using a second reagent. Investigation of metals will focus on the key issue of nucleation, with ruthenium serving as the model compound. The PI will further integrate the insights from these three topical areas to design molecular scaffolds for high density nucleation of ultrathin metal films on pre-functionalized surfaces. Transformative Aspects: This study can be potentially transformative as it will reveal the molecular transformations occurring during ALD/MLD processes, which will ultimately lead to novel strategies for film growth. Furthermore, this program will address one of the least understood processes in ALD, which is the initial nucleation of metals on different surfaces. Broader Impact: An inherent feature of the project is the emphasis on education and its integration with research. Specifically, three interrelated educational goals will be pursued: (a) development and assessment of a new interdisciplinary elective course in thin-film processing; (b) close mentorship and career counseling through research; and (c) participation in outreach programs designed to increase minority student recruitment and retention at the undergraduate level. The project also involves a graduate student exchange program with the Eindhoven University of Technology in The Netherlands, which will facilitate a intellectual and cultural experience for students at both institutions. The project addresses fundamental research issues in a topical area of materials science having high technological relevance in a variety of fields such as microelectronics, optoelectronics, and photovoltaics. The study is unique in the sense that it brings together a variety of state-of-the-art surface and gas-phase diagnostics to investigate gas-surface dynamics during deposition of thin films and nanolaminates through ALD and MLD. The general methodology and diagnostic tools will assist the PI is setting up a broader program for studying interfacial phenomena in other thin-film deposition processes, such as plasma-enhanced CVD. The multidisciplinary nature of the research encompasses physics, chemistry, engineering, and materials science. Besides development of new courses, several aspects of this work will be used to enhance existing courses in photovoltaics, plasma science, and microfabrication at CSM.