Measurement of the Al content in AlGaN epitaxial layers by combined energy‐dispersive X‐ray and electron energy‐loss spectroscopy in a transmission electron microscope

The purpose of this study is to use the two main techniques in analytical transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDXS) and energy-loss spectroscopy (EELS), to investigate the elemental distribution in different aluminium gallium nitride epitaxial layers grown by different methods. It is shown that an accurate EDX quantification is obtained when beam broadening and fluorescence of stray X-rays by the corundum substrate, Ga contamination due to focused ion beam (FIB) sample preparation and thickness-dependent k -factors are taken into account (T. Walther, Proc. EMAG 2009, Sheffield, J. Phys. Conf. Ser. 241, 012016 (2010) [1]). The EDXS quantification results are then compared to EELS quantification results. Both, analysis of Al and Ga K-lines by EDXS and analysis of Al K-line and Ga L-line in EELS can yield the Al content with a standard error of Δx ≈ 0.01–0.02 (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)