Measurement of electron beam induced sample heating in SEM experiments

Area of Science:

• Materials Science
• Analytical Chemistry
• Physics

Background:

• Scanning Electron Microscopy (SEM) offers high-resolution imaging and crystallographic analysis via Electron Backscatter Diffraction (EBSD).
• High-energy electron beams in SEM can cause localized heating, potentially compromising specimen integrity during extended analyses.
• Understanding and quantifying this electron-beam-induced heating is critical for accurate material characterization.

Purpose of the Study:

• To investigate and quantify electron-beam-induced heating effects on a model metal sample (iron).
• To determine the impact of various experimental parameters on localized sample temperature.
• To validate experimental measurements with simulation data.

Main Methods:

• Direct measurement of locally deposited electron beam energy using a MEMS-based heating device.
• Validation through Monte Carlo (MC) and Finite Element Method (FEM) simulations.
• Systematic variation of experimental parameters: acceleration voltage (5-30 kV), beam current (0.17-22 nA), dwell time (1µs-1 ms), and sample tilt (0°-70°).

Main Results:

• Local sample temperatures were observed to increase by up to 70 °C during Electron Backscatter Diffraction (EBSD) experiments.
• The primary experimental parameters influencing temperature increase are beam current and acceleration voltage.
• Beam current demonstrated the most significant impact on localized heating.

Conclusions:

• Electron beam heating is a significant factor in SEM/EBSD experiments, necessitating careful parameter selection.
• Accurate quantification of heating effects is achievable through combined experimental and simulation approaches.
• Optimizing experimental conditions based on these findings can preserve specimen integrity and improve data reliability.