Island dynamics and anisotropy during vapor phase epitaxy of m-plane GaN

Perret, Edith; Xu, Dongwei; Highland, M. J.; Stephenson, G. B.; Zapol, P.; Fuoss, P. H.; Munkholm, A.; Thompson, Carol

doi:10.1063/1.4993788

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Island dynamics and anisotropy during vapor phase epitaxy of m-plane GaN

Perret, Edith Materials Science Division, Argonne National Laboratory, Argonne, Illinois USA - University of Fribourg, Department of Physics and Fribourg Center for Nanomaterials, Fribourg, Switzerland
Xu, Dongwei Materials Science Division, Argonne National Laboratory, Argonne, Illinois USA - School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, China
Highland, M. J. Materials Science Division, Argonne National Laboratory, Argonne, Illinois USA
Stephenson, G. B. Materials Science Division, Argonne National Laboratory, Argonne, Illinois USA
Zapol, P. Materials Science Division, Argonne National Laboratory, Argonne, Illinois USA
Fuoss, P. H. Materials Science Division, Argonne National Laboratory, Argonne, Illinois USA - SLAC National Accelerator Laboratory, Menlo Park, CA USA
Munkholm, A. Munkholm Consulting, Mountain View, California USA
Thompson, Carol Department of Physics, Northern Illinois University, DeKalb, Illinois USA

04.12.2017

Published in:

Applied Physics Letters. - 2017, vol. 111, no. 23, p. 232102

English Using in situ grazing-incidence x-ray scattering, we have measured the diffuse scattering from islands that form during layer-by-layer growth of GaN by metal-organic vapor phase epitaxy on the (101⎯⎯0)(101¯0)(101¯0) m-plane surface. The diffuse scattering is extended in the (0001)(0001)(0001) in-plane direction in reciprocal space, indicating a strong anisotropy with islands elongated along [12⎯⎯10][12¯10] [12¯10] and closely spaced along [0001][0001][0001]. This is confirmed by atomic force microscopy of a quenched sample. Islands were characterized as a function of growth rate F and temperature. The island spacing along [0001][0001][0001] observed during the growth of the first monolayer obeys a power-law dependence on growth rate F−nF−nF−n, with an exponent n=0.25±0.02n=0.25±0.02n=0.25±0.02. The results are in agreement with recent kinetic Monte Carlo simulations, indicating that elongated islands result from the dominant anisotropy in step edge energy and not from surface diffusion anisotropy. The observed power-law exponent can be explained using a simple steady-state model, which gives n = 1/4.

Faculty

Faculté des sciences et de médecine

Department

Département de Physique

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