Ohmic contact formation to bulk and heterostructure gallium nitride family semiconductors

F. Rahman, S. Xu, I.M. Watson, D.K.B. Mutha, R.K. Oxland, N.P. Johnson, A. Bannerjee, E. Wasige

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We describe experiments investigating the quality of ohmic contacts to both bulk GaN and to III-nitride heterostructures. Titanium-based contacts were investigated to assess the role of intermixing and surface impurities for contact formation to n-type GaN. Direct contact to the two-dimensional electron gas in GaN/AlGaN heterostructures was also studied. These contacts were made by photochemical etching of the samples to expose the heterointerface. It was observed that even in the latter case contact annealing leads to a lower contact resistance by consuming surface contaminants and promoting beneficial interfacial reactions. Various passivation techniques were tried to reduce surface leakage current between contact pads and PECVD-deposited silicon nitride was found to be the best material for this application.
Original languageEnglish
Pages (from-to)633-639
Number of pages6
JournalApplied Physics A: Materials Science and Processing
Volume94
Issue number3
DOIs
Publication statusPublished - 15 Aug 2009

Keywords

  • ohmic contact formation
  • heterostructure
  • gallium nitride
  • semiconductors
  • photonics

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