GOALI: Fundamental Approaches to Atomic Layer Etching

非技术摘要：本计画将发展一次蚀刻一个原子的金属薄膜的科学与技术。这种专门技术在存储设备领域最为重要，特别是基于计算机、数码相机、移动的电话和其他类似设备中使用的磁性原理。与其他现代替代品相比，这些基于所开发技术的设备应表现出更低的功耗、更小的尺寸和更低的生产成本。然而，为了实现这一目标，需要对制造非常薄的金属层进行非常高水平的控制。这些层的厚度必须是高度可再现的，以确保可靠的存储器性能。对于所需的金属部件，难以通过传统方法存款它们;然而，可以存款这些材料的相对厚的层，然后以原子层精度将它们部分地蚀刻掉。 除了制造更简单，更便宜，更快和更可靠的存储设备的能力的明显优势之外，这项工作还可以影响处于国家利益核心的各种系统，包括航空航天和军事系统，图像存储和分析，数据记录和许多其他应用。在该项目中，大学和工业研究的结合将为学生提供特殊的教育和培训机会，并促进这种发展更快地进入市场。技术摘要：该GOALI项目将针对通过原子层蚀刻（ALEt）逐层去除沉积金属的新方法。ALEt的潜在应用的主要目标之一是在磁性随机存取存储器（MRAM）领域。原子层蚀刻（ALEt）需要使金属表面与前体分子反应，该前体分子使表面饱和并减少第一层原子与本体的结合。第二个输入，无论是化学的，能量的，还是两者的某种组合，都会导致第一层金属原子（及其相关配体）解吸。第二层原子现在将暴露于饱和前体，然后进行解吸步骤。随着过程的进行，原子将从表面逐层去除。沉积在Si衬底上的Fe、Co、Ni和Pt薄膜将用作初始靶。实验性的方法将采取两条轨道。首先，模型系统将被设计，建模和测试。这种方法将建立在通过研究原子层沉积（ALD）获得的理解之上。一套表面表征技术将与高分辨率显微镜相结合，以在原子水平上了解这些过程。在第二种方法中，与美国液化空气公司的合作将研究制造系统中的ALEt工艺，包括温度控制晶片卡盘、反应物质量流量控制器和等离子体源。这些系统也将配备，以便可以在操作中监测ALEt过程。将在特拉华州大学建造一个模型处理系统，以便在该过程的任何时候都可以对表面的成分和化学进行现场研究。在提案的最后，将开发各种材料的工作过程，包括MRAM应用中的重要材料。还将更深入地了解ALEt过程的物理组成部分。

NON-TECHNICAL ABSTRACT:This project will develop the science and technology for etching metallic films one atomic later at a time. This know-how is most important in the field of memory devices, specifically based on magnetic principles used in computers, digital cameras, mobile phones and other similar devices. These devices based on the technology developed should demonstrate lower power consumption, smaller sizes, and lower cost of production compared to the other modern alternatives. However, to achieve this goal, very high level of control over making very thin metallic layers is necessary. The thickness of these layers must be highly reproducible to ensure reliable memory performance. For the metal components required, it is difficult to deposit them by traditional methods; however, it is possible to deposit relatively thick layers of these materials and then partially etch them away with the atomic layer precision. In addition to the obvious advantages of capabilities to make simpler, cheaper, faster, and more reliable memory devices this work can affect a wide variety of the systems that are at the core of national interests, including aerospace and military systems, image storage and analysis, data logging and many other applications. The combination of university and industrial research in this grant will offer special educational and training opportunities to the students and facilitate this development to reach the marketplace more quickly.TECHNICAL ABSTRACT:This GOALI project will target new approaches for removal of deposited metals in a layer-by-layer manner through atomic layer etching (ALEt). One of the prime targets for potential application of ALEt is in the field of Magnetic Random Access Memory (MRAM). Atomic Layer Etching (ALEt) requires reacting a metallic surface with a precursor molecule that saturates the surface and reduces the binding of the first layer of atoms to the bulk. A second input, be it chemical, energetic, or some combination of the two, will cause the first layer of metal atoms (with their associated ligands) to desorb. The second layer of atoms will now be exposed to the saturating precursor, followed by the desorption steps. As the process proceeds, the atoms will be removed from the surface layer by layer. Fe, Co, Ni, and Pt thin films deposited on a Si substrate will be used as the initial targets. The experimental approach will take two tracks. First, model systems will be designed, modeled, and tested. This approach will build on the understanding obtained through studying atomic layer deposition (ALD). A suite of surface characterization techniques will be coupled with high-resolution microscopies to understand these processes at the atomic level. In the second approach, work with American Air Liquide will study the ALEt process in manufacturing systems including temperature controlled wafer chucks, mass flow controllers for the reactants, and plasma sources. These systems will also be equipped so that the ALEt process can be monitored in operando. A model processing system will be constructed at the University of Delaware so that the composition and chemistry of the surface can be studied at any point in the process, in-situ studies. At the end of the proposal, working processes for various materials, including those of importance in MRAM application, will be developed. A deeper understanding of the physical components of the ALEt process will also be achieved.