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Substrate-dependent wetting layer formation during GaN growth: Impact on the morphology of the films

Journal Article · · Journal of Applied Physics
DOI:https://doi.org/10.1063/1.2770869· OSTI ID:21057517
; ; ;  [1]
  1. Universitaet Tuebingen, Institut fuer Physikalische und Theoretische Chemie, Auf der Morgenstelle 8, D-72076 Tuebingen (Germany)
We have compared epitaxial growth of GaN films on 6H-SiC(0001)-({radical}(3)x{radical}(3))R30 deg. -Ga and on (0001)-sapphire. Predeposited Ga layers were nitrided by ion beam assisted molecular beam epitaxy. Whereas on SiC the initially deposited Ga covers the substrate surface completely, on sapphire only Ga droplets are present. The different distribution of the predeposited Ga affects the morphology of GaN significantly. Scanning electron microscopy and atomic force microscopy analysis of the grown films show that the complete wetting of the SiC substrate with Ga enhances finally the size and the flatness of GaN terraces and thus the quality of the film. X-ray photoelectron spectroscopy measurements reveal that metallic Ga resides also on top of the GaN films during the growth.
OSTI ID:
21057517
Journal Information:
Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 4 Vol. 102; ISSN JAPIAU; ISSN 0021-8979
Country of Publication:
United States
Language:
English