NON-DESTRUCTIVE DEPTH PROFILING BY MEANS OF SOFT X-RAY SPECTROMETRY AT MULTIPLE LOW VOLTAGES

摘要

At the EMAS 2015 workshop Takahashi et al.reported several unique features of the recently developed wavelength-dispersive soft X-ray emission spectrometer (WD-SXES) attached to EPMA and FEG-SEM. An energy resolution of 0.2 eV at the Al-L emission line was demonstrated. State-of-the-art FEG-SEM can achieve electron landing energies as low as 10 eV by applying a bias to the SEM stage. When combined with WD-SXES this opens up unique surface analytical possibilities. The present paper explores and demonstrates the unique capabilities of WD-SXES at multiple low voltages for outermost surface chemical analysis and non-destructive depth profiling. Several case studies will be discussed, including: 1. evolution of the Al-L spectrum in pure aluminium for electron landing energies increasing from 100 eV to 800 eV. 2. surface oxidation of beryllium; electron landing energies down to 200 eV were applied for surface chemical analysis. 3. depth distribution of boron dopant in a silicon device; the boron concentration was quantified from SXES peak area intensities for multiple voltages between 1 kV and 7 kV.