Electron Beam Induced Damage

Abstract

A next generation electron microscopes is currently being developed by the Department of Energy as a collaborative effort to redesign the instruments around aberration corrected optics [1]. Within this project, the TEAM 0.5 prototype microscope is currently being commissioned. The instrument is equipped with a high brightness gun and a monochromator [2]. However, already in the past concerns were raised [3] and debated [4] that the high current density in field emission microscopes may alter the atomic structure of materials too fast to record undamaged images of compound semiconductors. Concerns about electron beam induced knock-on damage are indeed very relevant because the TEAM project aims at reconstructing the three dimensional structure of materials at atomic resolution, which requires maintaining structural integrity. On the other hand detailed knowledge about knock-on and ionisation damage in such microscopes is absent and the TEAM0.5 microscope is ideally suited for such investigations since its unprecedented performance allows for the detection of single atoms of most elements of the periodic system [2].