[14p-PB10-1~1] 7.5 Atomic/molecular beams and beam-related new technologies

▲ [14p-PB10-1] Edge Contrast of Suspended Structures in
Nitrogen and Helium Ion Beam Secondary Electron Imaging

〇(P)Marek Schmidt¹, Hiroshi Mizuta^1,2 (1.JAIST, 2.Univ. of Southampton)

Keywords:Secondary electron,N2+ GFIS-FIB,HIM

Helium and nitrogen focused ion beams (FIB) generated from a gas field ion source (GFIS) offer high imaging capability due to their small beam spot size, depth of focus and unique material interaction. Back scattered ions can be used for imaging, but the yield is very low compared to the more common secondary electron imaging. In secondary electron images, the SE intensity is generally higher at vertical features due to the larger surface interaction area, and an intensity peak can be observed (so called “edge effect”). Recently we found that, for the edge of a 95 nm thick suspended Cr/Au thin film above SiO₂ (air gap g = 100 nm), a distinct decrease of the SE signal is observed close to the edge on the bottom surface. Here we present a simple model that can explain this observation.