Fundamental Study on the Etching Mechanics of Metal-Assisted Chemical Etching of Silicon for 2D and 3D Nanomanufacturing Applications

拟议的研究旨在了解金属辅助硅化学蚀刻（MaCE）中催化剂运动的基本机制。MaCE是一种新颖的方法，可以蚀刻复杂的2D和3D形状，例如表面下摆线和3D螺旋结构，同时保持1 nm量级的严格特征分辨率，即使纵横比为50：1。这些能力是通过以下事实实现的：当硅通过跨催化剂的电流反应被蚀刻时，限定蚀刻轮廓的金属催化剂行进到硅中，导致蚀刻轮廓在整个蚀刻长度上被紧密地保持，沿着通过控制催化剂运动来蚀刻3D结构的能力。粒子运动中涉及的基本动力学和力仍然是未知的和未研究的。拟议的研究将检查蚀刻剂的组成，催化剂的形状，催化剂的组成和外部领域如何影响的动力学和力的MaCE，以确定蚀刻速率，分辨率，形态和方向。此外，电场，力，催化剂运动和蚀刻形态的分析和计算模型将被开发。新的催化剂材料的动力学和形态学效应将被检查，并纳入模型。这项研究将提供一个更好的理解，如何动力学的MaCE沿着与催化剂粒子形状相互作用，以创造三维纳米结构，最终目标是提供精确的控制蚀刻方向。更先进的设备和纳米技术为科学家提供的机会，以探索自然界的基本性质在近原子水平。为了实现这些目标，世界各地的研究人员都在努力完善现有的技术，并开发新的纳米制造方法;然而，没有技术能够生产复杂的2D和3D纳米尺寸特征，具有高纵横比，光滑的壁，并且成本低。目前的纳米制造方法面临两个重要的限制。首先，3D几何形状如果不是不可能制造的话也是困难的，需要多个光刻步骤，这些光刻步骤既昂贵又不能很好地缩放到工业级制造要求。其次，随着特征尺寸缩小到纳米域，在大深度和高度上精确地保持这些特征变得越来越困难。生产这些结构的能力负担得起并且具有高精度对于许多现有的和新兴的技术是至关重要的，例如用于通信设备的高频带的超材料，用于以低成本检测癌症和其他疾病的先进生物芯片设备的纳米流体，用于快速、低成本制造的纳米压印光刻，所提出的研究旨在发展MaCE作为一种新方法的基本理解，以创建具有高特征保真度的2D和3D纳米结构，即使在高纵横比和低成本的情况下。世界各地的科学家正在寻求使用纳米材料来减少人类活动对环境的影响，拟议的研究将有助于实现这一目标所需的技术。

The proposed research seeks to understand the fundamental mechanisms involved in catalyst motion in Metal-assisted Chemical Etching of Silicon(MaCE). MaCE is a new, novel method to etch complex 2D and 3D shapes such as subsurface cycloids and 3D spiraling structures while maintaining tight feature resolutions on the order of 1 nm even with aspect ratios 50:1. These capabilities are enabled by the fact that the metal catalyst that defines the etching profile travels into the silicon as the silicon is etched by a galvanic reaction across the catalyst, resulting in etching profile is tightly maintained over the entire etch length along with the ability to etch 3D structures by controlling catalyst motion.While the stoichiometric chemistry of MaCE has been reasonably established, the fundamental kinetics and forces involved in particle motion have remain unknown and unstudied. The proposed research will examine how etchant composition, catalyst shape, catalyst composition and external fields affect the kinetics and forces of MaCE to determine etching rate, resolution, morphology and direction. Also, analytical and computational models of the electric fields, forces, catalyst motion and etching morphology will be developed. The kinetic and morphological effects of new catalyst materials will be examined and incorporated into the models. This research will provide a greater understanding on how the kinetics of MaCE along with the catalyst particleshape interact to create 3D nanostructures with the ultimate goal of providing precise control over etching direction.The considerable interest in nanomaterials and nanotechnology over the last decade is attributed to both the desire by industry for lower cost, more sophisticated devices and the opportunity that nano-technology presents for scientists to explore the fundamental properties of nature at near atomic levels. In pursuit of these goals, researchers around the world have worked to both prefect existing technologies and also develop new nano-fabrication methods; however, no technique exists that is capable of producing complex, 2D and 3D nano-sized features with high aspect ratios, smooth walls, and at low cost. Current nanofabrication methods face two important limitations. First, 3D geometry is difficult if not impossible to fabricate requiring multiple lithography steps that are both expensive and do not scale well to industrial level fabrication requirements. Second, as feature sizes shrink into the nano-domain, it becomes increasingly difficult to accurately maintain those features over large depths and heights. The ability to produce these structures affordably and with high precision is critically important to a number of existing and emerging technologies such as metamaterials for high-band with communication devices, nano-fluidics for advanced bio-on-a-chip devices to detect cancer and other disease at low cost, nano-imprint lithography for rapid, low cost fabrication, and more.The proposed research seeks to develop the fundamental understand of MaCE as a new method to create 2D and 3D nanostructures with high feature fidelity even at high aspect ratios and a low cost. Scientists around the world are looking to use nanomaterials to reduce the environmental impact of human activities and the proposed research will help enable the technology needed to achieve this goal.