Analysis of doping concentration and composition in wide bandgap AlGaN:Si by wavelength dispersive x-ray spectroscopy. (13th February 2017) - Kusch, Gunnar
Abstract: Detailed knowledge of the dopant concentration and composition of wide band gap Al x Ga 1 − x N 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 x Ga 1 − x N 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 × 10 18 cm −3 and 2.8 × 10 19 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.