EDX uses characteristic x-rays generated during the interaction of the primary electron beam with the atoms of the specimen to identify and quantify elements in the sample. The surface sensitivity of the method strongly depends on sample composition and acceleration voltage of the electron beam. Characteristic x-rays are typically produced in depths up to 2 µm. This should be taken into account, especially if, i.e., the specimen is composed of a stack of layers thinner than 1 µm.
SDD Apollo XV EDX detector (EDAX AMETEK)
- large detector area (10 mm2) allows high count rates; more than 200 kcps are possible
- energy resolution up to 130 eV
- liquid N2 free integrated thermo-electric cooling system
- Genesis 6.2 software package for data acquisition and processing
The example beneath shows measurements on a FIB cut perpendicular to the surface of a tin coated copper plate. The mappings were done at 20 kV and 32 nA with a dwell time of 200 µs over 30 frames and a count rate of 60k cps. The line scan was performed at 20 kV and 23 nA over 7.4 µm (151 points), a dwell time of 1000 ms per point and a count rate of 26k cps. The point analyses were done at 20 kV and 8 nA for 50 live seconds and with a count rate of 15k cps.