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

这笔赠款开发了新的蚀刻方法，以满足半导体行业在制造纳米级器件方面日益苛刻的需求。制造新型和先进的器件需要原子上精确地去除一堆复杂薄膜中的材料，每个薄膜都有几个纳米厚，同时保持表面光洁度和材料特性。原子层刻蚀(ALE)已经成为一种最可靠的一种一次去除一个原子层的材料的方法。对于单元素材料，这一整体的新颖策略已经被相对较好地理解；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，需要对合金和异质结构进行刻蚀。这笔赠款寻求所需的基础知识，以扩展ALE技术，以原子精度处理合金和异质结构。这些研究还可能解决一些障碍，将先进制造业的边界推向硅电子产品之外。解决这些问题所需的多学科方法将提供跨越物理、化学、材料科学和工程领域的高级培训机会，并将促进未被充分代表的群体参与科学和技术学科。这项研究将结合热化学蚀刻、材料物理和器件设计，以克服当前技术在以下方面的局限性：(1)选择性蚀刻由两种或两种以上金属和轻元素组成的复杂合金材料；(2)目标氧化层的自终止；以及(3)对厚氧化物层的精密蚀刻以实现非锥形垂直边缘。研究小组将使用分析光谱和显微镜方法以及计算机建模来确定影响特定元素蚀刻速率的动力学和热力学因素，并将它们结合起来定义复杂材料的原子精密蚀刻策略。这一策略的基础是选择适当的化学配体，选择性地结合到薄膜的每一种元素上，并确定用于设计蚀刻循环的参数，以便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NSF的法定使命，并通过使用基金会的智力优势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.