Growth and characterization of plasma-assisted molecular beam epitaxial-grown AlGaN/GaN heterostructures on free-standing hydride vapor phase epitaxy GaN substrates

D. F. Storm, D. S. Katzer, J. A. Mittereder, S. C. Binari, B. V. Shanabrook, Lin Zhou, David Smith, X. Xu, D. McVey, R. P. Vaudo, G. R. Brandes

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

We have grown AlGaN/GaN high electron mobility transistor (HEMT) structures by plasma-assisted molecular beam epitaxy on free-standing n -GaN substrates grown by hydride vapor phase epitaxy. Reflection high energy electron diffraction patterns of the as-loaded wafers exhibit narrow streaks which persist throughout the growth. Atomic force microscopy shows smooth AlGaN surfaces with root-mean-square roughness of 10 Å over a 20×20 μm2 area. High resolution x-ray diffractometry indicates that the AlGaN peak is ∼20% narrower than for similar structures grown on SiC. Hall mobilities, electron sheet densities, and sheet resistances were measured on ten 60×60 μm2 Hall test patterns defined photolithographically across the surface of the 10×10 mm2 sample. Buffer leakage measurements demonstrate that a Be:GaN layer effectively isolates the channel from the conductive substrate. Average sheet resistances and sheet densities were 380 Ω/□ and 0.94×1013 cm-2, respectively. These HEMT structures exhibit room-temperature Hall mobilities in excess of 1900 cm2V s. In addition, devices on these structures exhibit excellent pinch-off, low gate leakage, and saturated drain current densities of almost 700 mA/mm. Further details regarding the structural and electrical properties will be described along with device testing.

Original languageEnglish (US)
Pages (from-to)1190-1193
Number of pages4
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Volume23
Issue number3
DOIs
StatePublished - 2005

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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