Lattice strain measurement of nanoscale semiconductor devices is crucial for the semiconductor industry as strain substantially improves the electrical performance of transistors. High resolution scanning transmission electron microscopy (HR-STEM) imaging is an excellent tool that provides spatial resolution at the atomic scale and strain information by applying Geometric Phase Analysis or image fitting procedures. However, HR-STEM images regularly suffer from scanning distortions and sample drift during image acquisition. In this paper, we propose a new scanning strategy that drastically reduces artefacts due to drift and scanning distortion, along with extending the field of view. It consists of the acquisition of a series of independent small subimages containing an atomic resolution image of the local lattice. All subimages are then analysed individually for strain by fitting a nonlinear model to the lattice images. The method allows flexible tuning of spatial resolution and the field of view within the limits of the dynamic range of the scan engine while maintaining atomic resolution sampling within the subimages. The obtained experimental strain maps are quantitatively benchmarked against the Bessel diffraction technique. We demonstrate that the proposed scanning strategy approaches the performance of the diffraction technique while having the advantage that it does not require specialized diffraction cameras.

中文翻译：

---

用于局部测量纳米级应变的 HAADF-STEM 块扫描策略

纳米级半导体器件的晶格应变测量对于半导体行业至关重要，因为应变可显着提高晶体管的电气性能。高分辨率扫描透射电子显微镜 (HR-STEM) 成像是一种出色的工具，可通过应用几何相位分析或图像拟合程序提供原子尺度的空间分辨率和应变信息。然而，HR-STEM 图像在图像采集过程中经常受到扫描失真和样品漂移的影响。在本文中，我们提出了一种新的扫描策略，可以大大减少由于漂移和扫描失真引起的伪影，同时扩大视野。它由一系列独立的小子图像组成，这些子图像包含局部晶格的原子分辨率图像。然后通过将非线性模型拟合到晶格图像来单独分析所有子图像的应变。该方法允许在扫描引擎的动态范围的限制内灵活调整空间分辨率和视野，同时保持子图像内的原子分辨率采样。获得的实验应变图以贝塞尔衍射技术为基准进行定量。我们证明了所提出的扫描策略接近衍射技术的性能，同时具有不需要专门的衍射相机的优势。该方法允许在扫描引擎的动态范围的限制内灵活调整空间分辨率和视野，同时保持子图像内的原子分辨率采样。获得的实验应变图以贝塞尔衍射技术为基准进行定量。我们证明了所提出的扫描策略接近衍射技术的性能，同时具有不需要专门的衍射相机的优势。该方法允许在扫描引擎的动态范围的限制内灵活调整空间分辨率和视野，同时保持子图像内的原子分辨率采样。获得的实验应变图以贝塞尔衍射技术为基准进行定量。我们证明了所提出的扫描策略接近衍射技术的性能，同时具有不需要专门的衍射相机的优势。