Investigation of surface treatment schemes on n-type GaN and Al 0.20 Ga 0.80 N

Deepak Selvanathan, Fitih M. Mohammed, Jeong Oun Bae, Ilesanmi Adesida, Katherine H.A. Bogart

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37 Citations (Scopus)


The effects of Si Cl4 reactive-ion-etching (RIE) plasma treatment on n-GaN and n- Al0.20 Ga0.80 N surfaces, and the subsequent cleaning of the surfaces using ammonium hydroxide (N H4 OH), hydrochloric acid (HCl), and buffered oxide etch (BOE) solutions, have been investigated using x-ray photoelectron spectroscopy and Auger electron spectroscopy measurements. Of these cleaning schemes, BOE was found to be the most effective treatment to remove oxides from the surfaces of the Si Cl4 plasma treated samples. The Si Cl4 plasma treatment of GaN and AlGaN resulted in the blueshift of Ga-N (Ga3d) peaks to higher binding energies corresponding to a shift of the Fermi level (EF) toward the conduction band edge at the surface. It has been reported that this type of shift is caused by the creation of N vacancies, which act as n -type dopant [D. W. Jenkins and J. D. Dow, Phys. Rev. B. 39, 3317 (1989); M. E. Lin, Z. F. Fan, Z. Ma, L. H. Allen, and H. Morko̧, Appl. Phys. Lett. 64, 887 (1994); A. T. Ping, Q. Chen, J. W. Yang, M. A. Khan, and I. Adesida, J. Electron. Mater. 27, 261 (1998)] on the surface due to Si Cl4 plasma treatment. This corresponds to an increase in n -type dopant density on the surface. Thus, Si Cl4 plasma treatment in a RIE system thins the Schottky barrier heights of n-GaN and n-AlGaN and aids in the formation of ohmic contacts on such surfaces.

Original languageEnglish
Pages (from-to)2538-2544
Number of pages7
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Issue number6
Publication statusPublished - Nov 2005

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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