Low resistance bilayer Nd/Al ohmic contacts on n-type GaN

Ching Ting Lee, Ming Yuan Yeh, Chang Da Tsai, Yen Tang Lyu

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35 Citations (Scopus)


A bilayer Nd/Al metallization structure has been deposited onto low pressure organometallic vapor phase epitaxy grown n-type GaN (1 × 1018 cm-3) by electron-beam evaporation. Ohmic metal contacts were patterned photolithographically for standard transmission line measurement, and then thermally annealed at temperatures ranging from 200 to 350°C and from 500 to 650°C using conventional thermal annealing (CTA) and rapid thermal annealing (RTA), respectively. The lowest values for the specify contact resistivity of 9.8 × 10-6Ω-Cm2 and 8 × 10-6 Ω-cm2 were obtained using Nd/Al metallization with CTA of 250°C for 5 min and RTA of 600°C for 30 s. Examination of the surface morphology using atomic force microscopy as a function of annealing temperature revealed that the surface roughness was strongly influenced by conventional thermal annealing, it was smooth in the temperature range from 550 to 650°C for rapid thermal annealing. Auger electron spectroscopy depth profiling was employed to investigate the metallurgy and interdiffusion of contact formation.

Original languageEnglish
Pages (from-to)262-265
Number of pages4
JournalJournal of Electronic Materials
Issue number3
Publication statusPublished - 1997 Mar

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry


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