Detection of low-energy backscattered electron in scanning electron microscopy using microchannel plate detector

Area of Science:

• Materials Science
• Electron Microscopy
• Physics

Background:

• Silicon photodiodes (Si-PD) are standard backscattered electron (BSE) detectors in scanning electron microscopy (SEM).
• Si-PDs struggle to detect low-energy electrons below 3 kV, limiting SEM observation capabilities.
• A need exists for BSE detectors optimized for low-energy SEM imaging.

Purpose of the Study:

• To develop an alternative BSE detector for low-energy SEM observations.
• To overcome the limitations of Si-PDs in detecting low-energy electrons.
• To enable new SEM observation methods using low-energy BSE imaging.

Main Methods:

• Development of a thin microchannel plate (MCP) chip with an integrated energy filter grid.
• Utilizing the MCP detector for low-energy electron beam operation (down to 1 keV).
• Implementing energy filtering to separate secondary electron (SE) and BSE signals.

Main Results:

• The developed MCP detector successfully detects low-energy BSEs from 50 eV to 1 keV.
• Sufficient signal detection was achieved even at 1 keV electron beam operation.
• Energy filtering effectively isolated BSE signals, enabling clear low-energy BSE images.

Conclusions:

• The MCP detector with an energy filter provides a viable alternative for low-energy BSE detection in SEM.
• This technology expands SEM's observational range, particularly for low-energy electron imaging.
• The ability to filter SE components facilitates new low-energy BSE imaging techniques.