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

Si-photodiode is commonly used for the backscattered electron (BSE) detector in scanning electron microscope (SEM). However, it is difficult to detect low-energy electrons below 3 kV. We have developed a thin microchannel plate (MCP) chip with an energy filter grid as an alternative BSE detector for low-energy SEM observations. The MCP can get enough signals even at 1 keV electron beam operation. The energy filtering operation revealed that the MCP image is composed of SE and BSE signals. By filtering SE component, the low-energy BSE images are easily obtained, which will open-up the new observation method of SEM using low-BSE image.