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.
LanguageEnglish
Pages633-639
Number of pages6
JournalApplied Physics A: Materials Science and Processing
Volume94
Issue number3
DOIs
Publication statusPublished - 15 Aug 2009

Fingerprint

Gallium nitride
Ohmic contacts
gallium nitrides
Heterojunctions
electric contacts
Semiconductor materials
Impurities
Two dimensional electron gas
Contact resistance
Plasma enhanced chemical vapor deposition
Titanium
Surface chemistry
contact resistance
Silicon nitride
Passivation
silicon nitrides
Nitrides
Leakage currents
passivity
nitrides

Keywords

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

Cite this

Rahman, F. ; Xu, S. ; Watson, I.M. ; Mutha, D.K.B. ; Oxland, R.K. ; Johnson, N.P. ; Bannerjee, A. ; Wasige, E. / Ohmic contact formation to bulk and heterostructure gallium nitride family semiconductors. In: Applied Physics A: Materials Science and Processing. 2009 ; Vol. 94, No. 3. pp. 633-639.
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Ohmic contact formation to bulk and heterostructure gallium nitride family semiconductors. / Rahman, F.; Xu, S.; Watson, I.M.; Mutha, D.K.B.; Oxland, R.K.; Johnson, N.P.; Bannerjee, A.; Wasige, E.

In: Applied Physics A: Materials Science and Processing, Vol. 94, No. 3, 15.08.2009, p. 633-639.

Research output: Contribution to journalArticle

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AU - Rahman, F.

AU - Xu, S.

AU - Watson, I.M.

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AB - 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.

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