GOALI: Exploring Surface Interaction Mechanisms Enabling Plasma-Enhanced Atomic Layer Etching

1134273 Oehrlein来自马里兰州大学（College Park）和IBM研究院的PI计划研究表面相互作用机制，该机制将在半导体和相关行业的纳米级结构制造期间转移光刻定义的模板时，在蚀刻不同材料时实现原子精度。在场效应晶体管和其他器件中使用超薄栅极掩模、超薄沟道和低于20 nm的膜厚度需要原子级蚀刻控制和选择性。随着关键尺寸接近10 nm尺度，对原子层蚀刻（ALE）方法的需求变得至关重要。拟议的研究的目的是建立什么样的原子表面改性产生的几种模型材料，使用等离子体蚀刻相关的设备将使定向和控制的去除一个原子层的时间从这些表面。 研究人员将采用表面钝化的受控顺序反应，然后进行定向低能离子攻击以去除“挥发性产物”，以确定用于去除产物的反应性前体和/或高能离子/物质的自限行为可以为原型材料/蚀刻系统建立什么条件，以及这样的序列如何实现ALE。该方法包括用一系列单独的、自限性的表面反应来代替复杂的等离子体-表面相互作用步骤，在处理期间对表面改性/原子厚度变化进行定量的、时间分辨的实时表征，基于在超高真空系统中进行的互补真空束研究来开发表面改性/蚀刻模型，与理论前体吸附/离子-表面相互作用模型进行比较，以及使用各种等离子体反应器和侵略性缩放的半导体器件结构的上述工艺参数空间的工业研究，沿着对半导体器件制造空间的影响的分析和电气表征。这项工作的知识价值来自于这样一个事实，即对于各向异性ALE，“蚀刻产物”的去除必须以定向的方式进行，这与广泛使用的原子层沉积方法有根本的不同，在原子层沉积方法中各向同性反应提供保形涂层。阐明ALE的科学基础提出了新的入射粒子通量/表面化学的挑战和充满活力的物种/表面相互作用的问题，是独特的，并提供机会的主要贡献。更广泛的影响：项目任务的成功完成将使纳米级材料的受控精确图案化成为可能，这将影响未来设计不同领域所需制造工艺的努力，包括半导体，柔性碳基电子产品，医疗保健工程等。学术/工业合作为参与的学生，教师和研究人员提供了独特的教育机会。

1134273OehrleinThe PIs from University at Maryland (College Park) and IBM Research plan to study surface interaction mechanisms that will enable achievement of atomic precision in etching different materials when transferring lithographically defined templates during nanoscale structure fabrication in the semiconductor and related industries. The use of ultra-thin gate dielectrics, ultra thin channels, and sub-20 nm film thicknesses in field effect transistors and other devices requires atomic scale etching control and selectivity. As critical dimensions approach the 10 nm scale, the need for an Atomic Layer Etching (ALE) method becomes essential. The objective of the proposed research is to establish what atomistic surface modifications produced in several model materials using plasma etching related equipment will enable directional and controlled removal of one atomic layer at a time from those surfaces. The researchers will employ controlled sequential reactions of surface passivation followed by directional low energy ion attack for "volatile product" removal to establish for what conditions self-limiting behavior with regard to both the reactive precursors and/or energetic ions/species that are used to remove the products can be established for prototypical materials/etching systems and how such a sequence can enable ALE. The approach includes replacing complex plasma-surface interaction steps by a sequence of individual, self-limiting surface reactions, quantitative, temporally resolved real-time characterization of surface modifications/atomistic thickness changes during processing, development of surface modification/etching models based on complementary vacuum beam studies performed in an ultra-high vacuum system, comparisons with theoretical precursor adsorption/ion-surface interaction models, and industrial studies of the above process parameter space using a variety of plasma reactors and aggressively-scaled semiconductor device structures, along with analytical and electrical characterizations of the impact on the semiconductor device fabrication space.Intellectual Merit: The intellectual merit of this work derives from the fact that for anisotropic ALE, "etch product" removal must take place in a directional fashion, which is fundamentally different from widely used atomic layer deposition methods, where isotropic reaction(s) provide(s) a conformal coating. Elucidating the science underlying ALE presents novel incident particle flux/surface chemistry challenges and energetic species/surface interaction problems that are unique and offer opportunity for primary contributions. Broader Impacts: Successful completion of the project tasks will enable controlled precision patterning of materials at the nanoscale, which will impact future efforts to design manufacturing processes required in diverse areas, including semiconductors, flexible carbon-based electronics, healthcare engineering and others. The academic/industrial collaboration provides unique educational opportunities for the students, faculty and researchers involved.