G. Kusch¹, F. Mehnke², J. Enslin², P.R. Edwards¹, T. Wernicke², M. Kneissl^2,3, and R.W. Martin¹

Published in:

Semicond. Sci. Technol., vol. 32, no. 03, pp. 035020 (2017).

Abstract:

Detailed knowledge of the dopant concentration and composition of wide band gap Al_xGa_1-xN layers is of crucial importance for the fabrication of ultra violet light emitting diodes. This paper demonstrates the capabilities of wavelength dispersive x-ray (WDX) spectroscopy in accurately determining these parameters and compares the results with those from high resolution x-ray diffraction (HR-XRD) and secondary ion mass spectrometry (SIMS). WDX spectroscopy has been carried out on different silicon-doped wide bandgap Al_xGa_1-xN samples (x between 0.80 and 1). This study found a linear increase in the Si concentration with the SiH₄/group-III ratio, measuring Si concentrations between 3 × 10¹⁸ cm^-3 and 2.8 × 10¹⁹ cm^-3, while no direct correlation between the AlN composition and the Si incorporation ratio was found. Comparison between the composition obtained by WDX and by HR-XRD showed very good agreement in the range investigated, while comparison of the donor concentration between WDX and SIMS found only partial agreement, which we attribute to a number of effects.

Keywords:

nitrides, Si doping, WDX, AlGaN, SEM analysis.

Copyright © 2017 IOP Publishing Ltd. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IOP Publishing Ltd.

Full version in pdf-format.