Frank L, Zadrazil M, Müllerová I
Institute of Scientific Instruments AS CR, Brno, Czech Republic.
Scanning. 2001 Jan-Feb;23(1):36-50. doi: 10.1002/sca.4950230106.
A method for scanning electron microscopy imaging of nonconductive specimens, based on measurement and utilisation of a critical energy, is described in detail together with examples of its application. The critical energy, at which the total electron yield curve crosses the unit level, is estimated on the basis of measurement of the image signal development from the beginning of irradiation. This approach, concentrated onto the detected signal as the only quantity crucial for the given purpose of acquiring a noncharged micrograph, evades consequences of any changes in an irradiated specimen that influence the total electron yield curve and possibly also the critical energy value. Implementation of the automated method, realised using a cathode lens-equipped scanning electron microsope (SEM), enables one to establish a mean rate of charging over the field of view and its dependence on the electron landing energy. This dependence enables one to determine the energy of a minimum damage of the image of the given field of view. Factors influencing reliability and applicability of the method are discussed and examples of noncharged micrographs of specimens from both life and material science fields are presented.
本文详细描述了一种基于临界能量测量与利用的非导电样品扫描电子显微镜成像方法，并给出了应用实例。临界能量是指总电子产额曲线与单位水平相交时的能量，它是根据从辐照开始时图像信号的发展测量来估算的。这种方法专注于检测信号，将其作为获取无电荷显微照片这一特定目的的唯一关键量，避免了辐照样品中任何影响总电子产额曲线以及可能影响临界能量值的变化所带来的后果。使用配备阴极透镜的扫描电子显微镜（SEM）实现的自动化方法，能够确定视场中的平均充电速率及其对电子着陆能量的依赖性。这种依赖性使得人们能够确定给定视场图像的最小损伤能量。文中讨论了影响该方法可靠性和适用性的因素，并展示了生命科学和材料科学领域样品的无电荷显微照片实例。
