Effect of Ga dissolution in Au of Ni-Au system on ohmic contact formation to p-type GaN

Jiin Long Yang, Jen-Sue Chen

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

The effect of Ga dissolution in Au of Ni-Au system on ohmic contact formation to p-type GaN was carried out in this study. The Au (8 - x nm)/Ni (2 nm)/Au(x nm) deposited on p-GaN by magnetron sputtering system, where x = 0, 2, 4, and 6. It was discovered that after annealing in O2 ambient, the samples show ohmic characteristic when x is equal to 4 and 6. The TEM cross-sectional observation indicated that Ni did not diffuse to the GaN surface during annealing and the Ni transformed to NiO at the same time. The final microstructure became Au(8 - x)/NiO/Au(x)/p-GaN, where Au(8 - x) layer agglomerated into the semi-continuous and NiO was considered a barrier to prevent the diffusion of Ga atoms. Therefore, the presence of Au(x) plays a role to dissolve the Ga atoms from p-GaN, leaving Ga vacancies below the contact, thus increased the hole concentration of p-GaN. It is concluded that amount of Au(x) contacting to p-GaN is a key to achieve ohmic characteristics on p-GaN in this study.

Original languageEnglish
Pages (from-to)312-318
Number of pages7
JournalJournal of Alloys and Compounds
Volume419
Issue number1-2
DOIs
Publication statusPublished - 2006 Aug 10

All Science Journal Classification (ASJC) codes

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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