Enhanced lateral growth of AlN epitaxial layer on sapphire by introducing periodically pulsed-TMGa flows.
In: Superlattices & Microstructures, Jg. 131 (2019-07-01), S. 59-65
Online
academicJournal
Zugriff:
Crystal quality improvements of AlN epilayers grown on sapphire substrates has been achieved by using periodically pulsed-trimethylgallium (TMGa) flows (PTFs) in the initial growth stage of high-temperature AlN. The 400-nm-thick AlN layer deposited with this method demonstrated atomically flat surface, and the line widths of x-ray rocking curves were 40 and 245 arcsec for (002) and (105) reflections, respectively. GaN mole fraction was measured to be less than 0.6% in the AlN layer, indicating a surfactant effect of the PTFs. A combination of experimental characterizations and density functional theory calculations unveils that the improvements are ascribed to the supplement of Ga atoms and the enhanced surface migration of Al adatoms by using the PTFs which promotes the transition of growth mode from three-dimension to two-dimension one. • Crystal improvements of AlNwere achieved by introducing PTFs in the initial growth stage of high-temperature AlN. • Smoothened surface and decreased dislocations density are ascribed to the enhanced lateral growth of AlN by the PTFs. • DFT calculations demonstrate that the incorporated Ga atoms can promote the surface diffusion of Al adatoms. • The introduction of PTFs exhibits no observable effect on UV absorption of AlN epilayer. [ABSTRACT FROM AUTHOR]
Titel: |
Enhanced lateral growth of AlN epitaxial layer on sapphire by introducing periodically pulsed-TMGa flows.
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Autor/in / Beteiligte Person: | Qiu, Xinjia ; Lv, Zesheng ; He, Yingyou ; Wu, Zhisheng ; Jiang, Hao |
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Zeitschrift: | Superlattices & Microstructures, Jg. 131 (2019-07-01), S. 59-65 |
Veröffentlichung: | 2019 |
Medientyp: | academicJournal |
ISSN: | 0749-6036 (print) |
DOI: | 10.1016/j.spmi.2019.05.034 |
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