Published in Appl. Phys. Lett. 86, 121914 (2005).

Effects of Hydrogen on the Morphology and Electrical Properties of GaN grown by Plasma-assisted Molecular Beam Epitaxy

Y. Dong and R. M. Feenstra
Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
D. W. Greve
Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
J. C. Moore, M. D. Sievert, and A. A. Baski
Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284


We study the effect of introducing hydrogen gas through the RF-plasma source during plasma-assisted molecular beam epitaxy of GaN(0001). The well-known smooth-to-rough transition that occurs for this surface as a function of decreasing Ga flux in the absence of H is found to persist even with H present, although the critical Ga flux for this transition increases. Under Ga-rich conditions, the presence of hydrogen is found to induce step bunching (facetting) on the surface. Conductive atomic force microscopy reveals that leakage current through dislocation cores is significantly reduced when hydrogen is present during the growth.

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