Improvement of the interfaces in AlGaN/AlN super lattice grown by NH_3 flow-rate modulation epitaxy

摘要

AlGaN/AlN superlattices (SLs) are key building blocks for vertical emitting devices, especially in the deep UV spectral range. Abrupt interfaces of 30-pair AlGaN/AlN (6.6 nm/3.3 nm) SLs with an average Al composition of 55.3% have been grown by NH3 flow-rate modulation epitaxy (FME). The interface and surface morphology can be largely improved using this growth technique due to enhancement of the surface migration of Al atoms. Moreover, basal stacking faults at the interfaces are observed by high resolution transmission electron microscopy. A stress relieving model has been proposed to explain the forming of BSFs. (C) 2019 The Japan Society of Applied Physics