High mobility AlGaN/GaN heterostructures grown by plasma-assisted molecular beam epitaxy on semi-insulating GaN templates prepared by hydride vapor phase epitaxy

M. J. Manfra, N. G. Weimann, J. W.P. Hsu, L. N. Pfeiffer, K. W. West, S. Syed, H. L. Stormer, W. Pan, D. V. Lang, S. N.G. Chu, G. Kowach, A. M. Sergent, J. Caissie, K. M. Molvar, L. J. Mahoney, R. J. Molnar

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Abstract

We report on an extensive study of the growth and transport properties of the two-dimensional electron gas (2DEG) confined at the interface of AlGaN/GaN heterostructures grown by molecular beam epitaxy (MBE) on thick, semi-insulating GaN templates prepared by hydride vapor phase epitaxy (HVPE). Thick (∼20μm) GaN templates are characterized by low threading dislocation densities (∼5×10 8cm -2) and by room temperature resistivities of ∼10 8cm. We describe sources of parasitic conduction in our structures and how they have been minimized. The growth of low Al containing (x≤0.05) Al xGa 1-xN/GaN heterostructures is investigated. The use of low Al containing heterostructures facilitates the study of the 2DEG transport properties in the previously unexplored regime of carrier density n s≤2×10 12cm -2. We detail the impact of MBE growth conditions on low temperature mobility. Using an undoped HVPE template that was residually n type at room temperature and characterized an unusually low dislocation density of ∼2×10 8cm -2, we have grown an Al 0.05Ga 0.95N/GaN heterostructure with a record mobility of 75000cm 2/Vs at sheet density of 1.5×10 12cm -2 and T=4.2K. The same heterostructure design grown on a semi-insulating HVPE template yielded a peak mobility of 62000cm 2/Vs at a density of n s=1.7×10 12cm -2 and T=4.2K. The observation of the fractional quantum Hall effect at filling factor ν=5/3 in the AlGaN/GaN system is reported. It is also demonstrated that thick semi-insulating GaN templates grown by HVPE are a viable substrate for the growth of high electron mobility transistors. Typical Al 0.25Ga 0.75N/GaN heterostructures exhibit room temperature density of 1.0×10 13cm -3 and mobility of ∼1500cm 2/Vs. The dc and rf characteristics of transistors grown by MBE on a HVPE template are presented.

Original languageEnglish (US)
Pages (from-to)338-345
Number of pages8
JournalJournal of Applied Physics
Volume92
Issue number1
DOIs
StatePublished - Jul 1 2002
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Manfra, M. J., Weimann, N. G., Hsu, J. W. P., Pfeiffer, L. N., West, K. W., Syed, S., Stormer, H. L., Pan, W., Lang, D. V., Chu, S. N. G., Kowach, G., Sergent, A. M., Caissie, J., Molvar, K. M., Mahoney, L. J., & Molnar, R. J. (2002). High mobility AlGaN/GaN heterostructures grown by plasma-assisted molecular beam epitaxy on semi-insulating GaN templates prepared by hydride vapor phase epitaxy. Journal of Applied Physics, 92(1), 338-345. https://doi.org/10.1063/1.1484227