Effect of Al/N ratio during nucleation layer growth on Hall mobility and buffer leakage of molecular-beam epitaxy grown AlGaN/GaN heterostructures

D. F. Storm, D. S. Katzer, S. C. Binari, B. V. Shanabrook, Lin Zhou, David Smith

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

AlGaN/GaN high electron mobility transistor structures have been grown by plasma-assisted molecular beam epitaxy on semi-insulating 4H-SiC utilizing an AlN nucleation layer. The electron Hall mobility of these structures increases from 1050 cm 2/V s to greater than 1450 cm 2/V s when the Al/N flux ratio during the growth of the nucleation layer is increased from 0.90 to 1.07. Buffer leakage currents increase abruptly by nearly three orders of magnitude when the Al/N ratio increases from below to above unity. Transmission electron microscopy indicates that high buffer leakage is correlated with the presence of stacking faults in the nucleation layer and cubic phase GaN in the buffer, while low mobilities are correlated with high dislocation densities.

Original languageEnglish (US)
Pages (from-to)3786-3788
Number of pages3
JournalApplied Physics Letters
Volume85
Issue number17
DOIs
StatePublished - Oct 25 2004

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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