Simulation of X-Ray Diffraction Spectra for AlN/GaN Multiple Quantum Well Structures on AlN(0001) with Interface Roughness and Variation of Vertical Layers Thickness

Abstract

A detailed XRD analysis of AlN/GaN multiple quantum well (MQW) structures grown on AlN(0001) substrates is proposed. The effect of roughness on the 2 scans measured in Bragg diffraction for symmetrical reflections is investigated together with the effect of depth variation of the well and barrier thickness. As shown, the magnitude of depth variation of the well and barrier thickness results in an asymmetrical broadening of the satellite peaks of the 2 scans. Roughness causes their symmetrical expansion that allows separating the influence of both effects. Several reasons of asymmetrical broadening of satellite peaks are considered: variation of the thickness period, variation of the average lattice parameter inherent to the period, which depends on the thickness ratio of the layers in the period, and their combination. The efficiency of the described method is illustrated in detail by numerical simulations.

The effect of ion implantation on structural damage of сompositionally graded AlGaN layers

“…The error between the experimental and calculated 2θ/ω scans was determined as in Refs. [29,30]. For the samples under investigation, the fitting is additionally complicated by the low intensity of the fringes from the Al x Ga 1-x N layer and the relatively high intensity from the peak at the lower angles from the GaN substrate.…”

“…The profiles of the static Debye-Waller factor and the Kato correlation length were characterized with a common maximum. Second, the fitting criterion between the measured and simulated spectra is given as follows [30]:…”