W and WSix Ohmic contacts on p- and n-type GaN

X. A. Cao*, F. Ren, S. J. Pearton, A. Zeitouny, M. Eizenberg, J. C. Zolper, C. R. Abernathy, J. Han, R. J. Shul, J. R. Lothian

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


W and WSi Ohmic contacts on both p- and n-type GaN have been annealed at temperatures from 300 to 1000°C. There is minimal reaction (≤100 Å broadening of the metal/GaN interface) even at 1000°C. Specific contact resistances in the 10-5 Ω cm2 range are obtained for WSix on Si-implanted GaN with a peak doping concentration of ∼5× 1020 cm-3, after annealing at 950°C. On p-GaN, leaky Schottky diode behavior is observed for W, WSix and Ni/Au contacts at room temperature, but true Ohmic characteristics are obtained at 250-300°C, where the specific contact resistances are, typically, in the 10-2 Ω cm2 range. The best contacts for W and WSix are obtained after 700°C annealing for periods of 30-120 s. The formation of β- W2N interfacial phases appear to be important in determining the contact quality.

Original languageEnglish
Pages (from-to)1221-1225
Number of pages5
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Issue number4
StatePublished - 1999
Externally publishedYes


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