Charging effects in AlGaN/GaN heterostructures probed using scanning capacitance microscopy

K. V. Smith, X. Z. Dang, E. T. Yu, J. M. Redwing

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16 Scopus citations


Charging effects in an AlxGa1-xN/GaN heterostructure field-effect transistor epitaxial layer structure have been studied using scanning capacitance microscopy. Voltages of ≤6 V applied between an AlxGa1-xN/GaN sample structure and a conducting proximal probe tip are found to create trapped charge in both doped and undoped heterostructures. Scanning capacitance measurements obtained over a wide range of bias voltages allow the charge distribution to be mapped both laterally and in depth with submicron to nanometer scale spatial resolution. Scanning capacitance imaging as a function of bias voltage performed in conjunction with numerical capacitance-voltage simulations suggests that positive charge can be trapped at the AlxGa1-xN surface and within the GaN layer and negative charge can be trapped at or near the AlxGa1-xN/GaN interface.

Original languageEnglish (US)
Pages (from-to)2304-2308
Number of pages5
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Issue number4
StatePublished - 2000

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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