Ralf Degenhardt

Design and implementation of a detector for on-axis electrons for enabling enhanced imaging of topographical structures

A novel electron detection scheme for use in scanning electron microscopes is presented. The detector features enhanced imaging of topographical and especially high-aspect-ratio structures by selective detection of on-axis electrons. It consists of a magnetostatic beam separator which splits the on-axis backscattered and secondary electrons from the primary electron beam without causing first-order chromatic aberrations. The design concept has been proven by experimental evaluations which demonstrate the enhanced imaging capabilities of this new detector.

Electron beam column for in-line applications featuring enhanced imaging of high-aspect-ratio structures by selective detection of on-axis secondary electrons

The scanning electron microscope presented here allows for enhanced and selective detection of on-axis secondary electrons by a novel two-detector arrangement in combination with a beam separator. It is based on our high-resolution electron beam column. The off-axis secondary electrons are recorded by a conventional in-lens detector. The on-axis secondary electrons from the primary electrons and deflects them towards a scintillator-based detector. The detector for on-axis secondary electrons can either work in a stand-alone mode or in combination with the in-lens detector. Due to the symmetry of its deflection field, the beam separator causes no first-order chromatic aberrations to the primary beam and the spatial resolution is not deteriorated. A first experimental evaluation has demonstrated the enhanced capabilities of this system.