Local electronic properties of AlGaN/GaN heterostructures probed by scanning capacitance microscopy

K. V. Smith, E. T. Yu, J. M. Redwing, K. S. Boutros

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

Local electronic properties in AlxGa1-xN/GaN heterostructure field-effect transistor epitaxial layer structures are probed using scanning capacitance microscopy. Acquisition of scanning capacitance images over a wide range of bias voltages combined with theoretical analysis and numerical simulation allows the presence, detailed nature, and possible structural origins of nanometer- to micron-scale inhomogeneities in electronic structure to be elucidated. Substantial lateral variations in local threshold voltages for transistor channel formation are observed, at length scales ranging from submicron to >2 μm, and found to arise primarily from local variations in AlxGa1-xN layer thickness. Features in electronic structure are also observed that are consistent with the existence of networks of negatively charged threading edge dislocations, as might be formed at island coalescence boundaries during epitaxial growth. The negative charge associated with these structures appears to lead to local depletion of carriers from the channel in the AlxGa1-xN/GaN transistor epitaxial layer structure.

Original languageEnglish (US)
Pages (from-to)274-280
Number of pages7
JournalJournal of Electronic Materials
Volume29
Issue number3
DOIs
StatePublished - Mar 2000

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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