The impact of Ti/Al contacts on AlGaN/GaN HEMT vertical leakage and breakdown

Ben Rackauskas, Michael J. Uren, Steve Stoffels, Ming Zhao, Benoit Bakeroot, Stefaan Decoutere, Martin Kuball

Research output: Contribution to journalArticle (Academic Journal)peer-review

7 Citations (Scopus)
367 Downloads (Pure)


Enhanced leakage paths below Ti/Al based contacts to GaN-on-Si HEMTs have been identified and studied. Through a novel use of the quasi-static capacitance-voltage technique, the depth of these preferential leakage paths was determined to be ~1.6μm, extending down into the superlattice strain relief layer. Along these paths, the material resistivity was reduced by more than a factor of 100 compared to the uncontacted epitaxy. It is suggested that the cause of the additional leakage is decoration of dislocations. This result is important for understanding buffer transport, a critical parameter for breakdown and buffer charge storage.

Original languageEnglish
Article number4
Pages (from-to)1580-1583
Number of pages3
JournalIEEE Electron Device Letters
Issue number10
Early online date29 Aug 2018
Publication statusPublished - Oct 2018

Structured keywords

  • CDTR


  • AlGaN/GaN HEMT
  • Aluminum gallium nitride
  • Capacitance
  • Conductivity
  • Current measurement
  • Electric breakdown
  • Epitaxial growth
  • HEMTs
  • Ohmic contacts
  • Vertical breakdown
  • Vertical leakage


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