GOALI: Fundamental Approaches to Atomic Layer Etching

非技术摘要：这个项目将发展蚀刻金属薄膜的科学和技术，一次一个原子。这一技术诀窍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该表现出更低的功耗、更小的尺寸和更低的生产成本。然而，为了实现这一目标，有必要对制造非常薄的金属层进行非常高水平的控制。这些层的厚度必须高度可重复性，以确保可靠的存储性能。对于所需的金属部件，很难用传统方法沉积它们；然而，可以沉积相对较厚的这些材料层，然后以原子层的精度部分蚀刻掉它们。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外，这项工作还可以影响到作为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。在这项资助中，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，并促进这一发展更快地进入市场。技术摘要：这个目标项目将瞄准通过原子层蚀刻(ALET)以一层一层的方式去除熔敷金属的新方法。ALET潜在应用的主要目标之一是在磁随机存取存储器(MRAM)领域。原子层刻蚀(Alet)要求金属表面与前体分子发生反应，使表面饱和，并减少第一层原子与主体的结合。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(及其相关的配体)解吸。第二层原子现在将暴露在饱和的前体中，随后是解吸步骤。随着这个过程的进行，原子将从表面一层又一层地移除。我们将使用在硅衬底上沉积的Fe、Co、Ni和铂薄膜作为初始靶。实验方法将分两条路走。首先，将对模型系统进行设计、建模和测试。这种方法将建立在通过研究原子层沉积(ALD)而获得的理解的基础上。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合作将研究制造系统中的Alet工艺，包括温度控制的晶片卡盘、反应物的质量流量控制器和等离子体源。还将配备这些系统，以便可以在操作台中监测Alet过程。特拉华大学将建造一个模型处理系统，以便可以在过程的任何点上研究表面的成分和化学成分，并进行现场研究。在提案的最后，将制定各种材料的工作程序，包括那些在MRAM应用中具有重要意义的材料。还将实现对Alet过程的物理组成部分的更深入的理解。

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.