Nb-Ti/Al/Ni/Au based ohmic contacts to AlGaN/GaN

In this paper, we report on a novel Nb-Ti/Al/Ni/Au metallic system proposed to form ohmic contact to AlGaN/GaN heterostructure. The metallic system uses deposition of thin niobium layer as the first layer in contact with the AlGaN barrier layer before deposition of the conventional Ti/Al/Ni/Au metal...

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Bibliographic Details
Published inVacuum Vol. 82; no. 2; pp. 193 - 196
Main Authors Vanko, G., Lalinský, T., Mozolová, Ž., Liday, J., Vogrinčič, P., Vincze, A., Uherek, F., Haščík, Š., Kostič, I.
Format Journal Article
LanguageEnglish
Published Elsevier Ltd 29.10.2007
Subjects
Contact resistivity
CTLM method
Depth profiling
Metal-nitride phases
CTLM method
Contact resistivity
Metal-nitride phases
Depth profiling
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Summary:In this paper, we report on a novel Nb-Ti/Al/Ni/Au metallic system proposed to form ohmic contact to AlGaN/GaN heterostructure. The metallic system uses deposition of thin niobium layer as the first layer in contact with the AlGaN barrier layer before deposition of the conventional Ti/Al/Ni/Au metallic system. The fabrication and electrical characterization of the Nb-Ti/Al/Ni/Au based ohmic contacts are presented. We have shown that Nb-based ohmic contacts at optimal alloying temperatures seem to be superior to that of conventional Ti/Al/Ni/Au in both surface morphology and contact resistivity evaluation. Auger Electron Spectroscopy (AES) and Secondary Ion Mass Spectroscopy (SIMS) are also used to evaluate the improved ohmic contact formation.
ISSN:0042-207X
1879-2715
DOI:10.1016/j.vacuum.2007.07.020