Metal contacts to n-GaN

L. Dobos, B. Pécz, L. Tóth, Zs J. Horváth, Z. E. Horváth, A. Tóth, E. Horváth, B. Beaumont, Z. Bougrioua

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Al, Au, Ti/Al and Ti/Au contacts were prepared on n-GaN and annealed up to 900 °C. The structure, phase and morphology were studied by cross-sectional transmission and scanning electron microscopy as well as by X-ray diffraction (XRD), the electrical behaviour by current-voltage measurements. It was obtained that annealing resulted in interdiffusion, lateral diffusion along the surface, alloying and bowling up of the metal layers. The current-voltage characteristics of as-deposited Al and Ti/Al contacts were linear, while the Au and Ti/Au contacts exhibited rectifying behaviour. Except the Ti/Au contact which became linear, the contacts degraded during heat treatment at 900 °C. The surface of Au and Ti/Au contacts annealed at 900 °C have shown fractal-like structures revealed by scanning electron microscopy. Transmission electron microscopy and XRD investigations of the Ti/Au contact revealed that Au diffused into the n-GaN layer at 900 °C. X-ray diffraction examinations showed, that new Ti 2 N, Au 2 Ga and Ga 3 Ti 2 interface phases formed in Ti/Au contact at 900 °C, new Ti 2 N phase formed in Ti/Al contact at 700 and 900 °C, as well as new AlN interface phase developed in Ti/Al contact at 900 °C.

Original languageEnglish
Pages (from-to)655-661
Number of pages7
JournalApplied Surface Science
Volume253
Issue number2
DOIs
Publication statusPublished - Nov 15 2006

Keywords

  • Electrical properties
  • GaN
  • Solid phase reaction
  • Thin films
  • Transmission electron microscopy

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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