Growth of Ultra Thin Metal Alloy Films

超薄金属合金薄膜的生长

• 批准号: 0854345
• 负责人: John Ekerdt
• 金额: $ 35万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2013-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0854345&HistoricalAwards=false
• 关键词: Growth; Ultra; Thin; Metal; Alloy

0854345EkerdtThis research program investigates the growth of ultra thin (less than 9 nm) amorphous metal films on amorphous substrates. Chemical growth methods will be studied that include chemical vapor deposition and plasma-enhanced chemical vapor deposition. Guided by first-principles calculations, this research will examine the role of alloying elements, such as phosphorus, boron, silicon and tin on stabilizing an amorphous microstructure in ruthenium, cobalt, nickel and palladium films. The goal is to force an amorphous structure at the minimum alloy concentration so that the metal properties are retained. The research will focus on chemical and physical methods to increase the nucleation density or to alter the course of film assembly to realize continuous films that are 2-4 nm thick. Changes will be made to increase the defect density of the substrates and experiments will also explore selective surface passivants to block reaction on the growing metal and force additional nucleation on the substrate. The research objectives are an understanding of the enabling reactions and processes that will lead to the thinnest possible continuous film, and to an ultra thin film with amorphous character. The program of work will involve film growth and characterization studies and it will involve surface studies to elucidate how the precursors interact with the substrates as the ligands and substrates are modified. The research leverages the expertise and experimental infrastructure at the University of Texas to grow and characterize films and to study surface reactions. Bonding and reactions at the substrate surface and at the film interface will be explored. Film composition and chemical bonding will be followed using X-ray photoelectron spectroscopy, secondary ion mass spectrometry and low energy ion scattering spectroscopy. A full complement of characterization facilities will be used to study the films, including spectral ellipsometry, atomic force microscopy, X-ray scattering spectroscopy, and high resolution electron microscopy.Intellectual Merit: Metal films find applications in sensors, optics and microelectronics, and as the critical dimensions or size of the applications and systems decrease, the metal films thickness also must decrease to tens of atomic diameters at most and must have a specific microstructure. This program seeks to describe how films form, with an emphasis on nucleation and island coalescence, the evolution of interfacial layers that bind the film to the substrate, how properties of bulk materials scale with thickness, and precisely how short range order is preserved as the film thickness approaches thicknesses that are 5- 15 times the characteristic dimension of the Veronoi polyhedra.Broader Impacts of the Proposed Research This research is motivated in general by the central role ultra thin metal films on amorphous substrates have in applications such as electrodes, sensors, optics, thermal barriers, and diffusion barriers. This program seeks to explore the role and nature of short-range-order in the formation and stabilization of ultra thin amorphous metals. Further this program addresses and seeks to describe the interfacial and surface reactions that affect the evolution of the films as it transforms from nucleated islands to a coalesced, continuous film. Issues of nucleation and growth are common to both amorphous and polycrystalline films.The research will directly support the training of graduate students and indirectly provide opportunities for undergraduates to participate in open-ended research projects. The PI and the graduate student will develop an exhibit that will help explain the revolutionary and current devices that motivate this research, sensors and microelectronics, and introduce these concepts to the general public and to precollege students. They will present it and display it through a variety of University of Texas sponsored venues, such as the annual UT Open House and the Texas Memorial Museum.

0854345Ekert本研究项目研究在非晶态衬底上生长超薄(小于9 nm)非晶态金属薄膜。将研究化学生长方法，包括化学气相沉积和等离子体增强化学气相沉积。在第一性原理计算的指导下，这项研究将检验合金元素，如磷、硼、硅和锡在稳定Ru、Co、Ni和Pd薄膜中非晶态微结构方面的作用。其目的是在最小的合金浓度下强制形成非晶态结构，从而保持金属的性能。研究将集中在化学和物理方法，以提高成核密度或改变薄膜的组装过程，以实现厚度为2-4 nm的连续薄膜。将做出改变，以增加衬底的缺陷密度，实验还将探索选择性表面钝化剂，以阻止生长的金属上的反应，并迫使衬底上额外的形核。研究的目标是了解能够产生尽可能薄的连续薄膜和具有非晶态特征的超薄膜的使能反应和过程。该工作计划将涉及薄膜生长和表征研究，并将涉及表面研究，以阐明当配体和底物被修饰时，前体如何与底物相互作用。这项研究利用德克萨斯大学的专业知识和实验基础设施来生长和表征薄膜，并研究表面反应。将探索基片表面和薄膜界面上的结合和反应。使用X射线光电子能谱、二次离子质谱仪和低能离子散射谱对薄膜的成分和化学结合进行跟踪。将使用一整套的表征设备来研究这种薄膜，包括光谱椭偏仪、原子力显微镜、X射线散射光谱和高分辨率电子显微镜。智能优点：金属薄膜在传感器、光学和微电子领域有广泛的应用，随着应用和系统的临界尺寸或尺寸的减小，金属薄膜的厚度也必须减小到最多几十个原子直径，并且必须具有特定的微结构。该计划旨在描述薄膜如何形成，重点是成核和岛状结合，将薄膜与衬底结合的界面层的演变，块状材料的性质如何随厚度变化，以及当薄膜厚度接近Veronoi多面体特征尺寸的5-15倍时，如何准确地保持短程有序。本研究的广泛影响本研究的主要动机是非晶态衬底上的超薄金属薄膜在电极、传感器、光学、热障和扩散障碍等应用中所起的中心作用。该计划旨在探索短程有序在超薄非晶态金属的形成和稳定中的作用和性质。此外，本程序解决并试图描述当薄膜从成核岛转变为结合的、连续的薄膜时，影响薄膜演化的界面和表面反应。成核和生长问题是非晶膜和多晶膜的共同问题。这项研究将直接支持研究生的培养，并间接为本科生提供参与开放式研究项目的机会。PI和研究生将开发一个展览，帮助解释推动这项研究的革命性和当前的设备、传感器和微电子学，并向普通公众和大学预科学生介绍这些概念。他们将通过德克萨斯大学赞助的各种场所展示它，如一年一度的德克萨斯大学开放日和德克萨斯纪念博物馆。