The effects of reactive-ion-etching (RIE) plasma treatment on and surfaces, and the subsequent cleaning of the surfaces using ammonium hydroxide , 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 plasma treated samples. The plasma treatment of GaN and AlGaN resulted in the blueshift of Ga–N peaks to higher binding energies corresponding to a shift of the Fermi level 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 -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. Morkoç, 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 plasma treatment. This corresponds to an increase in -type dopant density on the surface. Thus, plasma treatment in a RIE system thins the Schottky barrier heights of and and aids in the formation of ohmic contacts on such surfaces.
Investigation of surface treatment schemes on n-type GaN and
Deepak Selvanathan, Fitih M. Mohammed, Jeong-Oun Bae, Ilesanmi Adesida, Katherine H. A. Bogart; Investigation of surface treatment schemes on n-type GaN and . J. Vac. Sci. Technol. B 1 November 2005; 23 (6): 2538–2544. https://doi.org/10.1116/1.2131078
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