The measurement was performed in-situ inside a high resolution scanning electron microscope (SEM), and the nature of the local electric field was characterized through secondary electron contrast images with the aid of Rutherford scattering theory.  This study demonstrates the potential of SEM imaging for obtaining information about the local electric field within microelectronic structures and devices.
SEM
The finite element method (FEM) simulation and the three-electrodes imaging experiment were also conducted, and the obtained two-dimensional electric field distribution agreed well with the FEM simulation, suggesting that the in-situ visualization technique could be useful for determining the local field enhancement behavior for various geometrical configurations and microscale structures. 
FEM