Epitaxial growth and self-organized superlattice structures in AlGaN filmsgrown by plasma assisted molecular beam epitaxy

Citation
E. Iliopoulos et al., Epitaxial growth and self-organized superlattice structures in AlGaN filmsgrown by plasma assisted molecular beam epitaxy, MAT SCI E B, 87(3), 2001, pp. 227-236
Citations number
17
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering
Journal title
MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY
ISSN journal
0921-5107 → ACNP
Volume
87
Issue
3
Year of publication
2001
Pages
227 - 236
Database
ISI
SICI code
0921-5107(200112)87:3<227:EGASSS>2.0.ZU;2-E
Abstract
Aluminum gallium nitride alloys were grown by molecular beam epitaxy and th eir film composition, structure and microstructure were investigated by Rut herford backscattering spectroscopy, Atomic Force Microscopy, X-ray diffrac tion, Transmission Electron Microscopy and High Resolution Electron Microsc opy. The kinetics of growth was investigated and the result show that at th e growth temperature of 750 degreesC the sticking coefficient of Ga varies monotonically from practically 0 to 1 as the growth varies from group-III t o -V rich regime. Correspondingly, the surface morphology changes from atom ically smooth in the group-III regime to relatively rough in the nitrogen-r ich regime. The X-ray diffraction and TEM studies revealed the existence of three types of spontaneously formed superlattice structures, along the [00 01] direction, with periodicities of 2-, 7- and 12-monolayers. While the tw o-monolayer ordering is preferred under group-V rich conditions of growth, the 7- and 12-monolayer ordering were observed under group-III rich conditi ons of growth. Off-axis X-ray diffraction shows the absence of in-plane ord ering and that periodic stacking faults are not present in the superlattice structures. (C) 2001 Elsevier Science B.V. All rights reserved.