The Design of a Reflection Electron Energy Loss Spectrometer Attachment for Low Voltage Scanning Electron Microscopy

Jonathan Chuah,Anjam Khursheed

doi:10.3390/ma14247511

Abstract

This paper presents the design of a reflection electron energy spectrometer (REELS) attachment for low voltage scanning electron microscopy (LVSEM) applications. The design is made by carrying out a scattered electron trajectory ray paths simulation. The spectrometer attachment is small enough to fit on the specimen stage of an SEM, and aims to acquire nanoscale spatially resolved REELS information. It uses a retarding field electrostatic toroidal sector energy analyzer design, which is able to lower the kinetic energies of elastically backscattered electrons to pass energies of 10 eV or less. For the capture of 1 keV BSEs emitted in the polar angular range between 40 to 50°, direct ray-tracing simulations predict that the spectrometer attachment will have an energy resolution of around 0.4 eV at a pass energy of 10 eV, and 0.2 eV at a pass energy of 5 eV. This predicted performance will make it a suitable REELS attachment for SEMs that use field emission electron sources.

Highlights

There is at present a critical need to develop material science analytical tools for low voltage scanning electron microscopes (LVSEMs)
LVSEMs have largely replaced the use of conventional SEMs for high-resolution imaging applications and greatly extended the kinds of specimens that can be observed [2,3,4,5]
They still have the disadvantage of not being able to function with the energy dispersive X-ray (EDX) spectroscopy technique

Summary

Introduction

There is at present a critical need to develop material science analytical tools for low voltage scanning electron microscopes (LVSEMs). LVSEMs have many well-known advantages over conventional scanning electron microscopes (SEMs) They have higher signal yields, a smaller beam/specimen interaction volume, greater surface information, and the possibility of minimizing charging effects while inspecting non-conductive specimens [1]. LVSEMs have largely replaced the use of conventional SEMs for high-resolution imaging applications and greatly extended the kinds of specimens that can be observed [2,3,4,5]. They still have the disadvantage of not being able to function with the energy dispersive X-ray (EDX) spectroscopy technique.

Methods

Results

Conclusion