Ultramicroscopy最新文献_第5页

Imaging domain boundaries of rubrene thin crystallites by photoemission electron microscopy rubrene薄晶的光电发射电子显微镜成像畴边界

IF 2 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-09-30 DOI: 10.1016/j.ultramic.2025.114239

Moha Naeimi, Katharina Engster, Waqas Pervez, Ingo Barke, Sylvia Speller

The progress of designing organic semiconductors is extensively dependent on the quality of prepared organic molecular assemblies, since the charge transport mechanism is strongly efficient in highly ordered crystals compared to amorphous domains. Here we present a comprehensive photoemission electron microscopy (PEEM) and time-of-flight (TOF) spectroscopic study of rubrene (

C_{48} H_{24}

) thin crystals focusing on recently developed orthorhombic crystalline morphologies applied in organic electronic devices. Using femtosecond pulsed lasers with photon energies between 3–6 eV, we explore the interplay between photoemission processes, crystal morphology, and defect states. In a 2-photon photoemission process (2PPE), the PEEM images reveal dominant emission localized at domain boundaries, indicating strong contributions from trap states. In contrast, in 1PPE nm excitation uniform emission across the crystal surface is observed, highlighting a fundamental difference in photoemission mechanisms. Furthermore, in the intermediate photon energy range, we identify a nonlinear, non-integer photon order, where mostly the triclinic morphology contributes to the emission, distinguishing it from the orthorhombic phase. These findings provide a new framework for assessing the quality and internal structure of organic semiconductor thin films via wavelength-dependent photoemission imaging and spectroscopy.

有机半导体设计的进展很大程度上取决于所制备的有机分子组件的质量，因为与非晶畴相比，高有序晶体中的电荷传输机制非常有效。在这里，我们提出了一个全面的光电发射电子显微镜（PEEM）和飞行时间（TOF）光谱研究rubrene （C48H24）薄晶体的重点是最近发展的正交晶体形态应用于有机电子器件。利用光子能量在3-6 eV之间的飞秒脉冲激光器，我们探索了光电过程、晶体形态和缺陷态之间的相互作用。在双光子发光过程（2PPE）中，PEEM图像显示主要的发射定位于域边界，表明陷阱态的贡献很大。相比之下，在1PPE nm激发下，观察到晶体表面均匀发射，突出了光电发射机制的根本差异。此外，在中间光子能量范围内，我们确定了非线性，非整数光子阶，其中主要是三斜形态有助于发射，将其与正交相区分开来。这些发现为利用波长相关光发射成像和光谱学来评估有机半导体薄膜的质量和内部结构提供了一个新的框架。

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引用次数: 0

Workflows for multimodal electron tomography using EELS and EDX and their application to a spinodally decomposed CuNiFe alloy 使用EELS和EDX的多模态电子断层扫描工作流程及其在单独分解的CuNiFe合金中的应用。

IF 2 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-09-29 DOI: 10.1016/j.ultramic.2025.114247

Tatiana Kormilina , Georg Haberfehlner , Thomas Mairhofer (Radlinger) , Ferdinand Hofer , Gerald Kothleitner

Spectroscopic electron tomography using EDX and EELS signals presents significant challenges in both data acquisition and processing, particularly when aiming for high-fidelity 3D reconstructions. In this work, we present complete workflows that address these challenges through scripting-based solutions for automated parallel acquisition of EDX and EELS tilt series on the same microscope, as well as post-processing methods for correlating datasets acquired on different instruments. We demonstrate the advantages of a multimodal joint reconstruction, especially for undersampled or noisy data, where the combination of signals improves the reconstruction quality and enables lower-dose acquisition strategies. The developed workflows are applied to a spinodal CuNiFe alloy sample with inherently low HAADF contrast, successfully resolving ambiguities in the structure of nanoscale precipitates.

使用EDX和EELS信号的光谱电子断层扫描在数据采集和处理方面都面临重大挑战，特别是在高保真3D重建时。在这项工作中，我们提出了完整的工作流程，通过基于脚本的解决方案，在同一台显微镜上自动并行采集EDX和EELS倾斜系列，以及将不同仪器上获得的数据集关联起来的后处理方法，解决了这些挑战。我们展示了多模态联合重建的优势，特别是对于欠采样或噪声数据，其中信号的组合提高了重建质量并实现了低剂量获取策略。开发的工作流程应用于具有固有低HAADF对比度的spinodal CuNiFe合金样品，成功地解决了纳米级析出物结构中的模糊性。

引用次数: 0

Growth and oxidation of ultra-thin Pt-Sn layers on Pt(111) by molecular and atomic oxygen 分子氧和原子氧在Pt（111）上生长和氧化超薄Pt- sn层。

IF 2 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-09-27 DOI: 10.1016/j.ultramic.2025.114243

N. Braud , L. Buß , L. Merte , H. Wallander , J.-O. Krisponeit , T. Schmidt , E. Lundgren , J.I. Flege , J. Falta

The preparation of ultra-thin PtSn-alloyed layers by molecular beam epitaxy was studied using low-energy electron microscopy (LEEM) and micro-diffraction (

μ

-LEED). Deposition at a sample temperature of 435 °C initially results in the formation of a Pt

_{3}

Sn/Pt(111) layer showing a (2 × 2) reconstruction. With continued Sn deposition, a Pt

_{2}

Sn/Pt(111) layer develops, showing a (

\sqrt{3} \times \sqrt{3}

)R30° reconstruction. An ultra-thin tin oxide was formed from the (2 × 2) surface by exposure to molecular oxygen at temperatures of 500 °C and 590 °C, respectively. LEED shows the evolution of a new surface structure, which could be identified as an incommensurate rectangular

(\begin{matrix} 2.3 & 0 \\ 1.8 & 3.6 \end{matrix})

reconstruction with lattice parameters of a = (6.4 ± 0.1) Å and b = (8.6 ± 0.1) Å present in three domains rotated by 120° with respect to each other. This structure can be related to the zigzag reconstructions found for similar ultra-thin oxide systems. Contrarily, the (

\sqrt{3} \times \sqrt{3}

)R30° structure showed no oxide formation even after extensive exposure to molecular oxygen. The usage of atomic oxygen, however, allows for oxidation of this surface and the growth of thicker oxides on both types of overlayers. At 500 °C this process is accompanied by substantial roughening of the surface.

采用低能电子显微镜（LEEM）和微衍射（μ-LEED）研究了分子束外延法制备超薄ptsn合金层。在435°C的样品温度下沉积，最初形成Pt3Sn/Pt（111）层，呈现（2 × 2）重构。随着Sn的持续沉积，形成Pt2Sn/Pt（111）层，呈现（3×3）R30°重构。在温度分别为500℃和590℃的条件下，将（2 × 2）表面暴露于分子氧中形成超薄氧化锡。LEED显示了一个新的表面结构的演变，该结构可以被识别为一个不相称的矩形2.301.83.6重构，晶格参数为a =（6.4±0.1）Å和b =（8.6±0.1）Å，存在于相互旋转120°的三个域中。这种结构可以与类似超薄氧化物体系的锯齿形重建有关。相反，（3×3）R30°结构即使在大量暴露于分子氧后也没有氧化形成。然而，原子氧的使用允许该表面氧化，并在两种类型的覆盖层上生长更厚的氧化物。在500°C时，该过程伴随着表面的大量粗化。

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引用次数: 0

Investigating the convergence properties of iterative ptychography for atomic-resolution low-dose imaging 原子分辨率低剂量成像中迭代平面成像的收敛特性研究。

IF 2 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-09-26 DOI: 10.1016/j.ultramic.2025.114245

Tamazouzt Chennit , Songge Li , Hoelen L. Lalandec Robert , Christoph Hofer , Nadine J. Schrenker , Liberato Manna , Sara Bals , Timothy J. Pennycook , Jo Verbeeck

This study investigates the convergence properties of a collection of iterative electron ptychography methods, under low electron doses (

< 1 0^{3}

e^{-} / Å^{2}

) and gives particular attention to the impact of the user-defined update strengths. We demonstrate that carefully chosen values for this parameter, ideally smaller than those conventionally met in the literature, are essential for achieving accurate reconstructions of the projected electrostatic potential. Using a 4D dataset of a thin hybrid organic–inorganic formamidinium lead bromide (FAPbBr₃) sample, we show that convergence is in practice achievable only when the update strengths for both the object and probe are relatively small compared to what is found in literature. Additionally we demonstrate that under low electron doses, the reconstructions initial error increases when the update strength coefficients are reduced below a certain threshold emphasizing the existence of critical values beyond which the algorithms are trapped in local minima. These findings highlight the need for carefully optimized reconstruction parameters in iterative ptychography, especially when working with low electron doses, ensuring both effective convergence and correctness of the result.

本研究研究了在低电子剂量（3e-/Å2）下一系列迭代电子型图方法的收敛特性，并特别关注了用户定义的更新强度的影响。我们证明，仔细选择该参数的值，理想情况下小于文献中常规遇到的值，对于实现投影静电势的准确重建至关重要。使用薄杂化有机-无机甲脒溴化铅（FAPbBr3）样品的4D数据集，我们表明，与文献中发现的相比，只有当物体和探针的更新强度相对较小时，才能实现收敛。此外，我们证明了在低电子剂量下，当更新强度系数降低到一定阈值以下时，重建的初始误差会增加，强调存在临界值，超过该临界值，算法就会陷入局部最小值。这些发现强调了在迭代平面摄影中需要仔细优化重建参数，特别是在低电子剂量下工作时，以确保有效收敛和结果的正确性。

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引用次数: 0

A new approach to SEM in-situ thermomechanical experiments through automation 一种自动化的SEM原位热力学实验新方法

IF 2 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-09-22 DOI: 10.1016/j.ultramic.2025.114244

A.D. Smith , D. Lunt , M. Taylor , A. Davis , R. Thomas , F. Martinez , A. Candeias , A. Gholinia , M. Preuss , J.M. Donoghue

Experiments within the scanning electron microscope (SEM) are increasingly being carried out to observe microstructural evolution under applied strain and/or temperature. In-situ experiments allow phenomena to be observed that would be missed during post-mortem analysis. However, in-situ experiments are traditionally limited by being very labour intensive with an operator required throughout, restricting experiments to what can be achieved within working hours. Here, we present a fully integrated, automated solution that can carry out complex experiments without user intervention. With this solution experiments can be programmed with specific experimental conditions such as strain and heating and cooling rates with data acquisition parameters to track and collect data across statistically relevant regions. Three case studies are presented to demonstrate the solution’s flexibility: multi-region strain mapping during mechanical loading, chemical mapping of the dissolution and coarsening of phases at high temperature, and orientation mapping during mechanical loading to understand deformation and grain rotation.

在扫描电子显微镜（SEM）内进行的实验越来越多地用于观察施加应变和/或温度下的微观结构演变。现场实验可以观察到死后分析中可能遗漏的现象。然而，原位实验传统上受限于非常劳动密集型，全程需要操作人员，将实验限制在工作时间内可以实现的目标。在这里，我们提出了一个完全集成的自动化解决方案，可以在没有用户干预的情况下进行复杂的实验。有了这个解决方案，实验可以编程与特定的实验条件，如应变和加热和冷却速率与数据采集参数跟踪和收集数据跨统计相关区域。为了证明该方法的灵活性，给出了三个实例：机械加载时的多区域应变映射，高温下相溶解和粗化的化学映射，以及机械加载时的取向映射，以了解变形和晶粒旋转。

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引用次数: 0

High-Resolution EELS in an aberration-corrected LEEM: Design of electrostatic transfer lenses for hemispherical filters 像差校正LEEM中的高分辨率EELS：半球形滤光片静电转移透镜的设计

IF 2 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-09-16 DOI: 10.1016/j.ultramic.2025.114238

Vincent Lemelin, Richard Martel

Recent advances in Low-Energy Electron Microscopy (LEEM), including the development of aberration-corrected (AC) systems, have significantly enhanced spatial resolution. However, further progress is limited by the energy resolution of current instruments. In this work, we propose a novel approach to address this limitation by integrating two Hemispherical Deflector Analyzers (HDAs) in tandem: the first serving to monochromatize the electron source, and the second to enhance the spectroscopic performance of AC-LEEM for Electron Energy Loss Spectroscopy (EELS). This dual-HDA configuration provides a clear pathway toward combining high spatial and energy resolution, expanding the capabilities of LEEM for advanced surface and materials characterization. This paper discusses various criteria for implementing these HDAs on a commercial AC-LEEM and presents more specifically the design of four transfer lenses (TLs) for electron transfer between the HDAs and the other optical components of the instrument. The use of a natural aberration correction scheme based on the dispersion-compensation (DC) principle is also discussed for maximum current throughput. Using ray-tracing simulations, we first show that the TL design can effectively decelerate/accelerate the electrons between 0.1 and 15 keV, thus respecting the high-voltage operation of the AC-LEEM. A double focus of the electron beam is also simulated so that the electron positions are conserved after transfer at the exit/entrance of the HDAs, an important condition for DC operation. Finally, ray-tracing simulations of the TLs show that the focal plane can be switched from the image plane to the back focal plane, allowing fast switching between diffraction and imaging modes.

低能电子显微镜（LEEM）的最新进展，包括像差校正（AC）系统的发展，显著提高了空间分辨率。然而，进一步的进展受到现有仪器能量分辨率的限制。在这项工作中，我们提出了一种新的方法，通过将两个半球偏转器分析仪（HDAs）串联在一起来解决这一限制：第一个用于电子源单色化，第二个用于增强AC-LEEM用于电子能量损失光谱（EELS）的光谱性能。这种双hda配置为结合高空间和能量分辨率提供了一条清晰的途径，扩展了LEEM用于高级表面和材料表征的能力。本文讨论了在商用AC-LEEM上实现这些hda的各种标准，并更具体地介绍了用于hda和仪器其他光学元件之间电子转移的四个转移透镜（TLs）的设计。本文还讨论了基于色散补偿（DC）原理的自然像差校正方案的使用，以获得最大的电流吞吐量。通过射线追踪模拟，我们首先证明了TL设计可以有效地在0.1到15 keV之间减速/加速电子，从而尊重交流leem的高压工作。模拟了电子束的双聚焦，使得电子在HDAs出口/入口转移后的位置守恒，这是直流运行的重要条件。最后，射线追踪模拟表明，焦平面可以从成像平面切换到后焦平面，从而可以在衍射和成像模式之间快速切换。

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引用次数: 0

Evaluating atomic counts in metal nanoclusters via scanning transmission electron microscopy 用扫描透射电子显微镜评价金属纳米团簇中的原子计数。

IF 2 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-09-15 DOI: 10.1016/j.ultramic.2025.114242

Keizo Tsukamoto , Naoyuki Hirata , Masahide Tona , Yoshihiro Nemoto , Atsushi Nakajima

Nanoscale metal atom aggregates, metal nanoclusters (NCs), exhibit unique electronic properties that strongly depend on the number of constituent atoms. Precise control over atomic composition is highly anticipated to advance NC-based materials science, particularly for fine-tuning photonic responses, catalytic reactivity, and electronic spin characteristics. In this study, we employed high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) to observe platinum (Pt) NCs immobilized on a substrate, enabling direct visualization of their deposition states, densities, and structures. The Pt NCs, containing 19 to 70 atoms with single-atom precision, were deposited onto TEM grids. By analysing STEM images, structural information indicative of a spherical shape was revealed, demonstrating a clear correlation between the number of atoms in Pt NCs and their observed diameters in the STEM, comparable to mass spectrometry assessments. This approach highlights estimation of the number of constituent atoms in metal NCs based on diameter distributions observed by STEM, providing valuable insight for size-dependent structural analysis and the exploration of their functionalized metal NCs.

纳米级金属原子聚集体，即金属纳米团簇（NCs），表现出独特的电子特性，这种特性强烈依赖于组成原子的数量。对原子组成的精确控制被寄予了很高的期望，以推进基于nc的材料科学，特别是对光子响应、催化反应性和电子自旋特性的微调。在这项研究中，我们使用高角度环形暗场扫描透射电子显微镜（HAADF-STEM）观察固定在衬底上的铂（Pt） nc，从而直接可视化其沉积状态、密度和结构。将含有19 ~ 70个原子的Pt纳米碳化物以单原子精度沉积在TEM网格上。通过分析STEM图像，揭示了指示球形的结构信息，表明Pt NCs中的原子数与其在STEM中观察到的直径之间存在明确的相关性，可与质谱评估相媲美。这种方法强调了基于STEM观察到的直径分布对金属nc中组成原子数量的估计，为尺寸依赖性结构分析和探索其功能化金属nc提供了有价值的见解。

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引用次数: 0

ETDMS: Efficient two-stage diffusion model for accelerated SEM image super-resolution ETDMS：加速扫描电镜图像超分辨率的高效两级扩散模型

IF 2 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-09-13 DOI: 10.1016/j.ultramic.2025.114226

Xuecheng Zhang , Zixin Li , Bin Zhang , Wenchao Meng , Yuefei Zhang , Chaojie Gu , Xianjue Ye , Ze Zhang

The scanning electron microscope (SEM) is a crucial tool for characterizing material microstructures, and it is renowned for its high resolution and depth of field. However, SEM image quality is affected by the scanning speed and resolution settings. When using SEM to capture fast-changing dynamic processes and other specific tasks, maintaining high image quality while using fast scanning mode is often tricky. To address these challenges, this paper introduces introduce an efficient two-stage diffusion model for accelerated SEM image super-resolution named ETDMS. The image denoising and super-resolution were divided into independent tasks based on SEM imaging principles and completed in two separate stages. Specifically, in Stage 2, a conditional lightweight encoder–decoder architecture SR network is proposed to replace the large U-Net in the traditional diffusion model and combine it with accelerated sampling technology to improve image generation efficiency. Experimental results prove that compared with previous super-resolution methods, the images generated by ETDMS significantly improve evaluation parameters, subjective visual quality, and detail generation.

扫描电子显微镜（SEM）是表征材料微观结构的重要工具，以其高分辨率和景深而闻名。然而，扫描电镜图像质量受扫描速度和分辨率设置的影响。当使用SEM捕捉快速变化的动态过程和其他特定任务时，在使用快速扫描模式的同时保持高图像质量通常是棘手的。为了解决这些问题，本文引入了一种有效的加速扫描电镜图像超分辨率的两阶段扩散模型——ETDMS。基于扫描电镜成像原理，将图像去噪和超分辨率划分为独立任务，分两个阶段完成。具体而言，在第二阶段，提出了一种条件轻量级编码器-解码器架构SR网络，以取代传统扩散模型中的大型U-Net，并将其与加速采样技术相结合，提高图像生成效率。实验结果证明，与以往的超分辨率方法相比，ETDMS生成的图像在评价参数、主观视觉质量和细节生成方面都有显著提高。

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引用次数: 0

Electron spin resonance spectroscopy in a transmission electron microscope 透射电子显微镜中的电子自旋共振光谱。

IF 2 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-09-13 DOI: 10.1016/j.ultramic.2025.114224

Antonín Jaroš , Johann Toyfl , Andrea Pupić , Benjamin Czasch , Giovanni Boero , Isobel C. Bicket , Philipp Haslinger

Coherent spin resonance methods such as nuclear magnetic resonance (NMR) and electron spin resonance (ESR) spectroscopy have led to spectrally highly sensitive, non-invasive quantum imaging techniques with groundbreaking applications in fields such as medicine, biology, and physics. Meanwhile, transmission electron microscopy (TEM) offers detailed investigations with sub-atomic resolution, but often inflicts significant radiation damage. Here we exploit synergies and report on an integration of ESR spectroscopy in a TEM. Our miniaturized ESR setup, optimized for microscopic sample sizes, is implemented on a standard TEM sample holder and leverages the strong magnetic field of the TEM polepiece to align and energetically separate spin states. This integration will facilitate in situ studies of spin systems and their dynamics, quantum materials, radicals, electrochemical reactions, and radiation damage — properties that have, until now, been difficult to access using conventional electron microscopic tools. Moreover, this development marks a significant technological advancement towards microwave-driven quantum spin studies with a highly controlled electron probe at the nanoscale.

相干自旋共振方法，如核磁共振（NMR）和电子自旋共振（ESR）光谱学，已经导致了光谱高度敏感，非侵入性的量子成像技术，在医学，生物学和物理学等领域具有开创性的应用。同时，透射电子显微镜（TEM）提供了亚原子分辨率的详细研究，但往往造成严重的辐射损伤。在这里，我们利用协同作用，并报告了ESR光谱在TEM中的集成。我们的小型化ESR装置针对微观样品尺寸进行了优化，可在标准TEM样品支架上实现，并利用TEM样品片的强磁场来对齐和能量分离自旋态。这种集成将促进自旋系统及其动力学、量子材料、自由基、电化学反应和辐射损伤的原位研究，这些特性到目前为止很难用传统的电子显微镜工具获得。此外，这一发展标志着在纳米尺度上使用高度可控的电子探针进行微波驱动量子自旋研究的重大技术进步。

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引用次数: 0

Novel technique for aluminum thin film thickness measurement using top view SEM-EDX in conjunction with electron beam simulation and machine learning 结合电子束模拟和机器学习的顶视图SEM-EDX铝薄膜厚度测量新技术

IF 2 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-09-08 DOI: 10.1016/j.ultramic.2025.114237

Tahsinul Huq , Yew Hoong Wong , Joon Huang Chuah , Chee-Keong Tan , Shuye Zhang

A novel method for determining aluminum thin film thickness using top view SEM and EDX measurements has been developed. Electron beam simulations are used as the reference training data to feed into a machine learning algorithm, which once trained can predict the thickness of the aluminum thin film from EDX characteristic x-ray count measurements for a set of three accelerating voltages. Unlike previous techniques which rely on a reference pure material sample or substrate signal to compare to, this method compares instead using ratios of EDX x-ray signals using different accelerating voltages. Since no substrate signal is required, the layer(s) below the aluminum thin film may be any material. High prediction accuracy was obtained for the training and test data for most data points, below 10 % for thicknesses above 40 nm on average, though some large errors remained. Investigation of the lateral dispersion of the incident electron beams showed that lateral dispersion increased with accelerating voltage. Since measurement of higher thicknesses requires higher accelerating voltages, the minimum feature size that can be accurately measured increases for higher thicknesses. Limitations include the requirement for aluminum to be the top layer, the requirement for consistency of beam current, low signal and excessive noise at low values of accelerating voltage, and the need to make many measurements at different voltages if the approximate range of the thin film thickness is not initially known.

提出了一种利用顶视图扫描电镜和EDX测量铝薄膜厚度的新方法。电子束模拟用作参考训练数据，输入机器学习算法，该算法经过训练后可以根据三种加速电压下的EDX特征x射线计数测量结果预测铝薄膜的厚度。与以往依赖参考纯材料样品或衬底信号进行比较的技术不同，该方法使用不同加速电压下EDX x射线信号的比率进行比较。由于不需要衬底信号，铝薄膜下面的层可以是任何材料。对于大多数数据点，训练数据和测试数据的预测精度较高，对于厚度大于40 nm的数据，平均预测精度低于10%，但仍存在较大的误差。对入射电子束的横向色散的研究表明，横向色散随加速电压的增加而增加。由于测量更高的厚度需要更高的加速电压，因此可以精确测量的最小特征尺寸随着厚度的增加而增加。限制包括要求铝为顶层，要求光束电流的一致性，在低加速电压值下的低信号和过度噪声，以及如果最初不知道薄膜厚度的近似范围，则需要在不同电压下进行多次测量。

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引用次数: 0