Microstructural analysis of thick AlGaN epilayers using Mg‐doped AlN underlying layer

Abstract

This paper reports the microstructural analysis of 20‐μm‐thick Al0.5Ga0.5N with improved crystalline quality owing to the use of a Mg‐doped AlN underlying layer. The threading dislocation density in 20‐μm‐thick Al0.5Ga0.5N on Mg‐doped AlN was 8.6×108cm‐2, which is about one‐fifth lower than that of Al0.5Ga0.5N on an undoped AlN underlying layer. The microstructural analysis was carried out to clarify dislocation behaviours in the Al0.5Ga0.5N layer on the Mg‐doped AlN underlying layer. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Growth of High‐Quality AlN and AlGaN Films on Sputtered AlN/Sapphire Templates via High‐Temperature Annealing

“…On the other hand, when the AlN regrowth layer is not inserted, three‐dimensional growth occurs from the initial stage of growth of AlGaN due to the roughness of the growth interface . Dislocations are predicted to bend during three dimensional growth . In thick AlGaN growth, AlGaN grows two‐dimensionally and has a relatively flat surface shape.…”

Deep-ultraviolet integrated photonic and optoelectronic devices: A prospect of the hybridization of group III–nitrides, III–oxides, and two-dimensional materials

“…By embedding the regrown AlN layer, dislocations were observed on the surface as 3D growth that assisted in relaxing the resultant compressive strain. Conversely, without the AlN regrowth layer, 3D growth arises because of the roughness of surfaces at grown layer interface, and hence the majority of dislocations were bent [436][437][438] . It was detected that while growing thick Al x Ga 1−x N layers, the growth process followed 2D be- [439] .…”