Presentation Information
[9a-N403-11]Simulation of Coulomb Effect in Facet Electron Sources
〇Takaya Satomi1, Yasunari Sohda1 (1.Univ. of Tsukuba)
Keywords:
scanning electron microscope
High-current electron sources are essential for advancing scanning electron microscope (SEM) performance. However, increasing emission current exacerbates the Coulomb effect, limiting the source performance. This study numerically investigates this effect by comparing a conventional facet-type source with a spherical-type source.Our simulations show that the facet source's reduced brightness saturates at a lower value. We found this limitation is primarily caused by the Coulomb effect from localized high-current emission at the facet edge, due to electric field concentration. Suppressing emission from this edge region significantly improves the source characteristics. These results suggest that controlling the emitter geometry, especially at the edge, is a key consideration for designing high-performance electron sources.