Ohmic contact formation to doped GaN

L. L. Smith, M. D. Bremser, E. P. Carlson, T. W. Weeks, Y. Huang, M. J. Kim, Ray Carpenter, R. F. Davis

Research output: Chapter in Book/Report/Conference proceedingConference contribution

25 Scopus citations


Ohmic contact strategies for n- and p-type GaN have been investigated electrically, chemically, and microstructurally using transmission line measurements, high-resolution EELS and cross-sectional TEM, respectively. The contributions to contact performance from work function differences, carrier concentrations, annealing treatments, and interface metallurgy have been examined. The contact materials of Ti, TiN, Au, and Au/Mg were deposited via electron beam evaporation; Al was deposited via thermal evaporation. As-deposited Al and TiN contacts to highly doped n-GaN were ohmic, with room-temperature specific contact resistivities of 8.6×10 -5 Ω·cm 2 and 2.5×10 -5 Ω·cm 2 respectively. The Ti contacts developed low-resistivity ohmic behavior as a result of annealing; TiN contacts also improved with further heat treatment. For p-GaN, Au became ohmic with annealing, while Au/Mg contacts were ohmic in the as-deposited condition. The performance, structure, and composition of different contact schemes varied widely from system to system. An integrated analysis of the results of this study is presented below and coupled with a discussion of the most appropriate contact systems for both n- and p-type GaN.

Original languageEnglish (US)
Title of host publicationMaterials Research Society Symposium - Proceedings
PublisherMaterials Research Society
Number of pages6
StatePublished - 1996
Externally publishedYes
EventProceedings of the 1995 MRS Fall Meeting - Boston, MA, USA
Duration: Nov 26 1995Dec 1 1995


OtherProceedings of the 1995 MRS Fall Meeting
CityBoston, MA, USA

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials


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