Performance of SEM scintillation detector evaluated by modulation transfer function and detective quantum efficiency...

Area of Science:

• Materials Science
• Imaging Technology
• Physics

Background:

• Traditional methods for evaluating Scanning Electron Microscope (SEM) detectors are limited.
• Modulation Transfer Function (MTF) and Detective Quantum Efficiency (DQE) have not been widely applied to individual SEM detectors.

Purpose of the Study:

• To present a novel approach for evaluating SEM detectors using MTF and DQE.
• To detail the measurement techniques and calculations for MTF and DQE in SEM detectors.
• To assess the imaging performance of different scintillators within an Everhart-Thornley detector.

Main Methods:

• Utilized a time-modulated electron beam to generate a defined input signal for detector characterization.
• Measured and calculated the MTF and DQE as a function of spatial frequency for the SEM detector.
• Evaluated the Everhart-Thornley scintillation detector with YAG:Ce, YAP:Ce, and CRY18 single-crystal scintillators.

Main Results:

• The MTF and DQE characterization method was successfully applied to the Everhart-Thornley detector.
• Detectors employing YAP:Ce or CRY18 scintillators demonstrated excellent imaging properties.
• The influence of different electron beam scan types (point-by-point vs. continual-sweep) on image quality was analyzed using MTF.

Conclusions:

• The application of MTF and DQE provides a significant benefit for describing and understanding SEM detector performance.
• YAP:Ce and CRY18 scintillators are recommended for enhanced SEM imaging, particularly with specific electron beam scanning strategies.
• This novel approach offers a more comprehensive evaluation of SEM detector capabilities.