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Author Smith, M. D. ♦ Parbrook, P. J. ♦ O.'Mahony, D. ♦ Conroy, M. ♦ Schmidt, M.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ ALUMINIUM NITRIDES ♦ ANNEALING ♦ DIFFUSION ♦ ELECTRIC CURRENTS ♦ ELECTRIC POTENTIAL ♦ ELECTRON MOBILITY ♦ FIELD EMISSION ♦ GALLIUM NITRIDES ♦ INTERFACES ♦ LAYERS ♦ METALS ♦ SEMICONDUCTOR MATERIALS ♦ TEMPERATURE DEPENDENCE ♦ TEMPERATURE RANGE 0400-1000 K ♦ THICKNESS ♦ TRANSISTORS ♦ TRANSMISSION ELECTRON MICROSCOPY
Abstract This paper correlates the micro-structural and electrical characteristics associated with annealing of metallic multi-layers typically used in the formation of Ohmic contacts to InAlN high electron mobility transistors. The multi-layers comprised Ti/Al/Ni/Au and were annealed via rapid thermal processing at temperatures up to 925 °C with electrical current-voltage analysis establishing the onset of Ohmic (linear IV) behaviour at 750–800 °C. In-situ temperature dependent transmission electron microscopy established that metallic diffusion and inter-mixing were initiated near a temperature of 500 °C. Around 800 °C, inter-diffusion of the metal and semiconductor (nitride) was observed, correlating with the onset of Ohmic electrical behaviour. The sheet resistance associated with the InAlN/AlN/GaN interface is highly sensitive to the anneal temperature, with the range depending on the Ti layer thickness. The relationship between contact resistivity and measurement temperature follow that predicted by thermionic field emission for contacts annealed below 850 °C, but deviated above this due to excessive metal-semiconductor inter-diffusion.
ISSN 00036951
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-09-14
Publisher Place United States
Journal Applied Physics Letters
Volume Number 107
Issue Number 11


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