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Proceedings Paper

The influence of substrate nucleation on HVPE-grown GaN thick films
Author(s): Tongbo Wei; Ruifei Duan; Junxi Wang; Jinmin Li
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Paper Abstract

Thick GaN films were grown on sapphire in a home-made vertical HVPE reactor. Effect of nucleation treatments on the properties of GaN films was investigated, including the nitridation of sapphire, low temperature GaN buffer and MOCVD-template. Various material characterization techniques, including AFM, SEM, XRD, CL and PL have been used to assess these GaN epitaxial films. It was found that the surface of sapphire after high temperature nitridation was flat and showed high density nucleation centers. In addition, smooth Ga-polarity surface of epitaxial layer can be obtained on the nitridation sapphire placed in air for several days due to polarity inversion. This may be caused by the atoms re-arrangement because of oxidation. The roughness of N-polarity film was caused by the huge inverted taper domains, which can penetrate up to the surface. The low temperature GaN buffer grown at 650 °C is favorable for subsequent epitaxial film, which had narrow FWHM of 307 arcsec. The epitaxial growth on MOCVD-template directly came into quasi-2D growth mode due to enough nucleation centers, and high quality GaN films were acquired with the values of the FWHM of 141 arcsec for (002) reflections. After etching in boiled KOH, that the total etch-pit density was only 5×106 cm-2 illustrated high quality of the thick film on template. The photoluminescence spectrum of GaN film on the MOCVD-template showed the narrowest line-width of the band edge emission in comparison with other two growth modes.

Paper Details

Date Published: 4 January 2008
PDF: 9 pages
Proc. SPIE 6841, Solid State Lighting and Solar Energy Technologies, 684105 (4 January 2008); doi: 10.1117/12.760035
Show Author Affiliations
Tongbo Wei, Institute of Semiconductors (China)
Ruifei Duan, Institute of Semiconductors (China)
Junxi Wang, Institute of Semiconductors (China)
Jinmin Li, Institute of Semiconductors (China)

Published in SPIE Proceedings Vol. 6841:
Solid State Lighting and Solar Energy Technologies
Jinmin Li; Yuwen Zhao; Nuofu Chen; Ling Wu; Yubo Fan; Vladimir M. Andreev; Yong-Hang Zhang; Jai Singh; Michael E. Coltrin, Editor(s)

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