New Etching Methodologies for Atomic Level Precision in Manufacturing Processes at the Micro-to-Nanoscale

该基金开发新的蚀刻方法，以满足半导体工业中制造纳米级器件日益苛刻的需求。新型先进设备的制造需要原子精确地去除一堆复杂薄膜中的材料，每个薄膜的厚度为几纳米，同时保持表面光滑和材料特性。原子层蚀刻（ALE）已成为一次去除一个原子层材料的最可靠的方法。对于单元素材料，这种整体新颖的策略已经得到了相对较好的理解；然而，实际应用中的主要挑战，如存储器，逻辑器件，处理和信息传输，需要合金和异质结构的蚀刻。这项资助旨在寻求扩展ALE技术以原子精度处理合金和异质结构所需的基础知识。这些研究还可能解决一些障碍，推动先进制造业超越硅电子产品的边界。解决这些问题所需的多学科方法将提供物理、化学、材料科学和工程交叉领域的高级培训机会，并将促进科学和技术学科中代表性不足的群体的参与。该基金支持的研究将结合热化学蚀刻，材料物理学和设备设计，以克服当前技术的局限性：(1)由两种或多种金属和轻元素组成的复杂合金材料的选择性蚀刻，(2)目标氧化层的自终止，(3)厚氧化层的精密蚀刻以实现非锥形垂直边缘。研究小组将利用分析光谱学和显微镜方法，结合计算机建模，确定影响特定元素蚀刻速率的动力学和热力学因素，并将它们结合起来，确定复杂材料的原子精密蚀刻策略。该策略是基于选择合适的化学配体，选择性地结合到膜的每个元素，并确定设计蚀刻周期的参数，可以在不改变元素浓度和表面形貌的情况下逐层去除材料。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This grant develops new etching methods to meet the increasingly demanding needs in fabricating nanoscale devices within the semiconductor industry. The fabrication of novel and advanced devices requires atomically precise removal of materials in a stack of complex thin films, each of several nanometers thick, while maintaining surface smoothness and material properties. The atomic layer etching (ALE) has emerged as the most reliable method to remove materials one atomic layer at a time. This overall novel strategy has been relatively well understood for single element materials; however, the major challenge in practical applications, such as memory, logic devices, processing and information transfer, requires etching of alloys and heterostructures. This grant seeks the fundamental knowledge needed to extend the ALE technology to process alloys and heterostructures with atomic precision. The studies may also solve a number of hurdles to pushing the boundary of advanced manufacturing beyond silicon electronics. The multidisciplinary approach required to tackle these problems will offer advanced training opportunities in crossing fields of physics, chemistry, materials science, and engineering, and will advance the participation of underrepresented groups in science and technology disciplines. The research supported by this grant will combine thermal chemical etching, materials physics, and device design to overcome the limitations of current technologies in (1) selective etching of complex alloy materials consisting of two or more metals and light elements, (2) self-termination at target oxide layers, and (3) precision etching of thick oxide layers to achieve non-tapered vertical edges. The research team will use analytical spectroscopy and microscopy methods together with computer modeling to determine kinetic and thermodynamic factors responsible for the etching rates of specific elements and combine them to define the strategy for atomic precision etching of complex materials. This strategy is based on selecting appropriate chemical ligands that bind to each element of the films selectively and determining the parameters for designing etching cycles that can remove the materials layer-by-layer without altering the concentration of the elements and morphology of the surface.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.