An Advanced SEM-FIB Dual Beam Microscope for Three-Dimensional Mesoscale Fabrication, Imaging and Analysis

为了利用所用材料的全部三维特性，现在已经发展了现代结构和设备的生长和制造。无论是结构材料，如超细陶瓷-金属复合材料，还是功能材料，在功能材料中，晶体管结构由关键部件的3D“网格”组成，迫切需要从三维角度了解现代材料的结构、组成和物理化学性质。在过去的5年里，我们开发了透射式电子断层扫描技术，以纳米级的分辨率研究许多材料体系的内部结构，包括多相催化剂、纳米管和量子点。然而，重要的是要将许多长度尺度上的结构-性质关系联系起来，从纳米(10-9m)到微米(10-6m)到毫米(10-3m)。虽然X射线层析成像和相关技术在几微米的长度尺度上取得了很大的效果，但这项建议致力于技术的发展，使人们能够在从10‘S微米到10纳米的介观尺度上分析一系列材料的结构和成分，从而弥合了透射式电子断层成像和X射线断层成像之间的差距。这种三维分析现在可以使用扫描电子显微镜(SEM)/聚焦离子束(FIB)显微镜进行。这种仪器被称为“双光束显微镜”，它使用镓离子束的研磨作用来显示内部表面，并使用电子束来记录连续的图像切片(以获得3D形态)。可以使用二次电子(以获得最大的表面细节)或背向散射电子(具有原子序数对比)来形成图像。该仪器将配备一个场发射枪(FEG)电子源，以实现最佳亮度和图像分辨率，以及先进的分析工具，包括用于3D晶体研究的电子背散射衍射(EBSD)探测器，以及用于绘制3D样品成分图的能量色散X射线(EDX)探测器系统。它将有一个内部微操作器来处理微米大小的样品，并将包括一个现场应变阶段，以测量微米大小的部件的机械响应。除了产生结合电子和离子源的新的研究领域外，双束的单个组件将具有比我们目前可用的任何单束扫描电子显微镜和FIB更好的性能。特别是，EBSD系统将比我们目前的系统快约100倍，球磨时间最高可减少到FIB的1/5。除了3D成像和分析，我们还建议使用双光束工作站来制造新的电子设备结构，并为广泛的最先进的透射电子显微镜技术开发新的样品几何结构。特别是，对于透射电子显微镜样品，本建议中要求的双束允许膜的低能离子减薄以消除注入损伤。随后将取出的独立薄膜放到专门准备的栅格上进行微操作，然后在透射电子显微镜中允许360度完全倾斜和旋转，这对先进的电子断层扫描分析至关重要。

The growth and fabrication of modern structures and devices has now developed in order to exploit the full three-dimensional behaviour of the materials used. Whether its in structural materials, such as ultra-fine ceramic-metal composites, or in functional materials, where transistor structures composed of a 3D 'latticework' of key components, there is a pressing need to understand the structure, composition and physico-chemical properties of modern materials in three dimensions. Over the past 5 years we have developed transmission electron tomographic techniques to investigate, with nanometre resolution, the internal architecture of many materials systems, including heterogeneous catalysts, nanotubes and quantum dots. However, it is important to link the structure-properties relationships over many length scales, from nanometres (10-9m) to microns (10-6m) through to millimetres (10-3m). Although, x-ray tomography and related techniques are used with great effect at length scales ~ few microns, this proposal addresses the development of techniques to give the ability to analyse, in three dimensions, the structure and composition of a range of materials at a meso-scale, from 10's microns to 10 nm, bridging the gap between transmission electron tomography and x-ray tomography.Such 3D analysis can now be undertaken using a combined scanning electron microscope (SEM) / focussed ion beam (FIB) microscope. This instrument, known as a 'Dual Beam microscope', uses the milling action of a gallium ion beam to reveal internal surfaces and an electron beam to record successive image slices (to give 3D morphology). Either secondary electrons (for maximum surface detail) or back-scattered electrons (which has atomic number contrast) can be used to form images.The instrument will have a field emission gun (FEG) electron source for optimum brightness and image resolution, and advanced analytical tools including an electron backscattered diffraction (EBSD) detector for 3D crystallographic studies, and an energy-dispersive X-ray (EDX) detector system to map the composition of the specimen in 3D. It will have an internal micromanipulator for handling micron-sized specimens and an in-situ straining stage will be incorporated to measure the mechanical response of micron-sized components. As well as yielding new areas of research combining electron and ion sources, the individual components of the Dual Beam will have a performance better than any of the single-beam SEMs and FIB currently available to us. In particular, the EBSD system will be ~100x faster than our present system and milling times with the FIB reduced by up to a factor of 5.In addition to the 3D imaging and analysis, we propose to use a dual beam workstation to fabricate novel electronic device structures and develop novel sample geometries for a wide range of state-of-the-art transmission electron microscopic techniques. In particular, for TEM specimens the dual beam requested in this proposal allows low energy ion thinning of membranes to remove implantation damage. Subsequent micromanipulation of the plucked free-standing membrane onto a specially prepared grid will then allow full 360 degree tilt and rotation when in the TEM, vital for advanced electron tomographic analysis.