SEM with EDX and EBL System – LEO 1525 / Raith Elphy Plus

Elisa Sogne, Marco Asa
Authorized user
Yellow Room


The LEO 1525 is a high resolution FE-SEM. The field emission gun allows the user to produce a small probe with high current density for better resolution and enhanced microanalysis. The microscope has a standard Everhardt-Thornley secondary electrons detector for topographic imaging and an in-lens detector for surface specific imaging. The microscope may be run at accelerating voltages from 0.5kV to 20kV and the resolution of the microscope is 1.5nm at 20kV and 3.5nm at 1kV. It features high probe current and stability better than 0.5% per hour. Beside secondary electrons detectors, a chemical microanalysis system Bruker Quantax EDS is available for semiquantitave compositional investigation and mapping of samples through Energy Dispersive X-ray Analysis (EDX). Our SEM is equipped with a RAITH ELPHY Plus pattern generator for electron beam lithography. ELPHY Plus pattern processor has been designed with utmost care to deliver unexcelled electronic performance. This is an undeniable prerequisite for nanolithography with ultimate resolution, precision and stability – specifically if attached to modern thermal field emission based SEMs with high beam current densities.

Working principle

The Gemini objective lens design combines electrostatic and magnetic fields to maximize optical performance while reducing field influences at the sample to a minimum. This enables excellent imaging, even on challenging samples such as magnetic materials. The Gemini in-lens detection concept ensures efficient signal detection by detecting secondary (SE) and backscattered (BSE) electrons in parallel minimizing time-to-image. Gemini beam booster technology guarantees small probe sizes and high signal to-noise ratios. A sketch of the electron gun and SEM chamber can been seen in figure. (

Cross Section of a Scanning Electron Microscope



  • Stage XY range 10 cm
  • Column technology: Gemini
  • Accelerating voltages: 0.5kV to 20kV
  • Detectors: In-lens, secondary electrons, EDX
  • EBL maximum writefield: 5×5 mm
  • EBL ultimate resolution: 20 nm
  • EDX energy resolution (calibrated Mn Kalpha: 123.8 eV)