RBS/PIXE channeling for InAlGaN epitaxial layers

Abstract

Characteristics of InAlGaN quaternary alloy epitaxial layers have for the first time been studied by Rutherford backscattering spectrometry (RBS) and particle induced X-ray emission (PIXE). We have evaluated the crystalline quality from the normalized yield as a function of aluminium content of the InAlGaN quaternary alloy epitaxial layers with the same indium content. The compositions of the samples were estimated to be In0.02Al0.12Ga0.86N and In0.02Al0.24Ga0.74N from RBS measurements. The normalized yield for an In0.02Al0.12Ga0.86N epitaxial layer and an In0.02Al0.24Ga0.74 epitaxial layer was calculated to be 2.44% and 4.20%, respectively. This indicates that they have excellent crystalline quality and that the crystalline quality of the epitaxial layer becomes worse with increase of the aluminum content. PIXE channeling has also been performed for both samples. Individual signals of indium and aluminum atoms in InAlGaN epitaxial layers were obtained by PIXE measurements. The normalized yield of the indium was smaller than that of the aluminum in both InAlGaN epitaxial layers which suggest the differences of their lattice vibration or atomic displacements.