Introduction

There is increasing need for the micro-analyst to correctly determine chemical composition of regions

on the sub-micron scale. Field emission SEMs offer an ideal tool for these tasks due their excellent

spatial resolution and high brightness sources. However, in order to analyze these types of samples the

accelerating voltage of the electron beam is commonly in the range 1-5kV. Traditionally when working

at these voltages low count rates necessitated the use of EDS detectors with large crystals to maximize

collection solid angle. Analysis using EDS at low kV is, however, complicated by the large number of

overlapped X-ray lines seen in this part of the spectrum. New field emission SEMs that offer high

currents at low kV are opening new opportunities to use the higher spectral resolution and sensitivity

of WDS to analyze samples on the sub-micron scale.