MSE 2016 - Full Program

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Highlight Lecture

Low Voltage Scanning Electron Microscopy (LVSEM) with the EsB Detector: Applications in Microelectronics and Photovoltaics

Thursday (29.09.2016)
11:45 - 12:00
Part of:

Scanning Electron Microscopy studies at standard conditions do not allow to detect small composition differences, and damage during observation is a concern for beam sensitive samples. In this study, we will show that the optimization of the working conditions in Low Voltage Scanning Electron Microscopy (LVSEM) in combination with an Energy selective Backscattered (EsB) electron detector enhances the material contrast and mitigates electron beam-induced damage effects. Mitigation of sample damage is of particular interest for thin films and organic samples. In the case of Organosilicate Glass (OSG) thin films, used as insulating material with low permittivity between the metal on-chip interconnects in leading-edge microelectronic products, the glass network is densified during the electron beam-sample interaction which phenomenologically causes a significant shrinkage of the material [1]. By combining a low accelerating voltage (Ep = 1 kV) with the EsB detector, the material contrast is increased and the shrinkage phenomena is significantly mitigated (Figure 1d)). By controlling the grid bias of the EsB detector, the electron energy can be filtered and the secondary electrons (SE), which are responsible for the topographical information, and the backscattered electrons (BSE) with high or moderate energy loss, are cut off. Then it is increased the influence to the signal of the low-loss BSEs (LLBSE), which mainly carry material contrast information and have undergone a small number of inelastic scattering events. Figure 2 shows two images of the blend ZnPc (Zn-Phtalocyanine) and C60 (fullerene), used as active layer for organic solar cells. The morphology of the donor (ZnPc) and acceptor (C60) phases in the active layer is the key to improving the power conversion efficiency of organic solar cells. Therefore, it is crucial to identify and characterize this morphology. By applying lower Ep, the material contrast between the blend compounds is detectable and enhanced with the EsB detector (Fig 2b)), since small contrast differences are obtained from the LLBSE [2], which come from the very shallow regions of the blend surface and not from the volume where multiple inelastic scattered electrons are produced, like in the SE image of Fig. 2a)

Additional Authors:
  • Mona Sedighi
    Technical University Dresden
  • Dr. Markus Loeffler
    Technical University Dresden
  • Dr. Willem F. van Dorp
    Technical University Dresden
  • Dr. Rüdiger Rosenkranz
    Fraunhofer Institute for Ceramic Technologies and Systems (IKTS)
  • Prof. Dr. Ehrenfried Zschech
    Technical University Dresden


Category Short file description File description File Size
Manuskript Figure 1 Figure 1 from the abstract 253 KB Download
Manuskript Figure 2 Figure 2 from the abstract 423 KB Download
Manuskript Abstract Abstract with figures, acknowledgements, references and keywords 252 KB Download