Study of threading dislocation density reduction in AlGaN epilayers by Monte Carlo simulation of high‐resolution reciprocal‐space maps of a two‐layer system. (18th January 2013)

• Record Type: Journal Article
• Authors: Lazarev, S.; Barchuk, M.; Bauer, S.; Forghani, K.; Holý, V.; Scholz, F.; Baumbach, T.
• Is Part Of: Journal of applied crystallography. Volume 46:Part 1(2013:Feb.)
• Page Start: 120
• Page End: 127
• Publication Date: 2013-01-18
• Subjects: Crystallography -- Periodicals; 548.05
• DOI: 10.1107/S0021889812043051
• Languages: English
• ISSNs: 0021-8898

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>High‐resolution X‐ray diffraction in coplanar and noncoplanar geometries has been used to investigate the influence of an SiN<italic>_x</italic> nano‐mask in the reduction of the threading dislocation (TD) density of high‐quality AlGaN epitaxial layers grown on sapphire substrates. Our developed model, based on a Monte Carlo method, was applied to the simulation of the reciprocal‐space maps of a two‐layer system. Good agreement was found between the simulation and the experimental data, leading to an accurate determination of the dislocation densities as a function of the overgrowth layer thickness. The efficiency of the SiN<italic>_x</italic> nano‐mask was defined as the ratio of the TD densities in the AlGaN layers below and above the mask. A significant improvement in the AlGaN layer quality was achieved by increasing the overgrowth layer thickness, and a TD density reduction scaling law was established.</p> </abstract>