Crystallographic Tilt in Aluminum Gallium Nitride Epilayers Grown on Miscut Aluminum Nitride Substrates. Issue 1 (25th October 2022)

• Record Type: Journal Article
• Authors: Rathkanthiwar, Shashwat; Graziano, Milena B.; Tweedie, James; Mita, Seiji; Kirste, Ronny; Collazo, Ramon; Sitar, Zlatko
• Is Part Of: Physica status solidi. Volume 17:Issue 1(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-10-25
• Subjects: AlGaN -- AlN substrates -- strain relaxation -- tilt; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.202200323
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : Heteroepitaxial crystallographic tilt has been investigated as a possible strain‐relief mechanism in Al‐rich (Al>50%) AlGaN heteroepitaxial layers grown on single‐crystal (0001) AlN substrates with varying miscuts from 0.05° to 4.30°. The magnitude of the elastic lattice deformation‐induced tilt increases monotonically with the miscut angle, tightly following the Nagai tilt model. Although tilt angles as high as 0.1° are recorded, reciprocal space mapping (RSM) broadening and wafer bow measurements do not show any significant changes as a function of the heteroepitaxial tilt angle. While crystallographic tilting has been shown to be effective in controlling strain in some other heteroepitaxial systems, it does not provide any appreciable strain relief of the compressive strain in AlGaN/AlN heteroepitaxy. Abstract : The magnitude of heteroepitaxial crystallographic tilt increases monotonically with the miscut angle, in accordance with the Nagai tilt model. Although some elastic strain accommodation is expected for very thin layers, crystallographic tilt is ineffective in strain relief for thick AlGaN heteroepitaxial layers.