Space charge cartography by FLIMM on SEM-irradiated PTFE thin films

This article presents the results obtained by Focused Laser-Intensity Modulation Method (FLIMM) on polytetrafluoroethylene (PTFE) thin films irradiated by electron beam. The positioning of a metallic grid on the sample before irradiation permits to select the irradiated zones. A laser surface scanning allows retrieving the charge boxes and determining their implanted depth. Different studies for various grid pitches and spot sizes fix the lateral resolution which we can attain at around 10 μm. Finally, the space charge evolution with time is presented and gives an indication of their migration inside the structure.