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Title: Microstructure of V-based ohmic contacts to AlGaN/GaN heterostructures at a reduced annealing temperature

Abstract

Ohmic contacts with V/Al/Ni/Au and V/Ni/Au metalization schemes were deposited on AlGaN/GaN heterostructures. The dependence of the specific contact resistance on the annealing conditions and the V:Al thickness ratio was shown. For an optimized electrode stack, a low specific contact resistance of 8.9 × 10{sup −6} Ω cm{sup 2} was achieved at an annealing temperature of 650 °C. Compared to the conventional Ti/Al/Ni/Au contact, this is a reduction of 150 K. The microstructure and contact formation at the AlGaN/metal interface were investigated by transmission electron microscopy including high-resolution micrographs and energy dispersive X-ray analysis. It was shown that for low-resistive contacts, the resistivity of the metalization has to be taken into account. The V:Al thickness ratio has an impact on the formation of different intermetallic phases and thus is crucial for establishing ohmic contacts at reduced annealing temperatures.

Authors:
; ; ;  [1];  [2]; ;  [3]
  1. Institute of Applied Physics, TU Bergakademie Freiberg, 09599 Freiberg (Germany)
  2. Namlab gGmbH, 01187 Dresden (Germany)
  3. Institute of Materials Science, TU Bergakademie Freiberg, 09599 Freiberg (Germany)
Publication Date:
OSTI Identifier:
22420280
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM; ALUMINIUM COMPOUNDS; ANNEALING; DEPOSITS; ELECTRIC CONDUCTIVITY; ELECTRIC CONTACTS; GALLIUM NITRIDES; GOLD; MICROSTRUCTURE; NICKEL; TRANSMISSION ELECTRON MICROSCOPY; VANADIUM; X RADIATION

Citation Formats

Schmid, A., E-mail: alexander.schmid@physik.tu-freiberg.de, Schroeter, Ch., Otto, R., Heitmann, J., Schuster, M., Klemm, V., and Rafaja, D.. Microstructure of V-based ohmic contacts to AlGaN/GaN heterostructures at a reduced annealing temperature. United States: N. p., 2015. Web. doi:10.1063/1.4907735.
Schmid, A., E-mail: alexander.schmid@physik.tu-freiberg.de, Schroeter, Ch., Otto, R., Heitmann, J., Schuster, M., Klemm, V., & Rafaja, D.. Microstructure of V-based ohmic contacts to AlGaN/GaN heterostructures at a reduced annealing temperature. United States. doi:10.1063/1.4907735.
Schmid, A., E-mail: alexander.schmid@physik.tu-freiberg.de, Schroeter, Ch., Otto, R., Heitmann, J., Schuster, M., Klemm, V., and Rafaja, D.. Mon . "Microstructure of V-based ohmic contacts to AlGaN/GaN heterostructures at a reduced annealing temperature". United States. doi:10.1063/1.4907735.
@article{osti_22420280,
title = {Microstructure of V-based ohmic contacts to AlGaN/GaN heterostructures at a reduced annealing temperature},
author = {Schmid, A., E-mail: alexander.schmid@physik.tu-freiberg.de and Schroeter, Ch. and Otto, R. and Heitmann, J. and Schuster, M. and Klemm, V. and Rafaja, D.},
abstractNote = {Ohmic contacts with V/Al/Ni/Au and V/Ni/Au metalization schemes were deposited on AlGaN/GaN heterostructures. The dependence of the specific contact resistance on the annealing conditions and the V:Al thickness ratio was shown. For an optimized electrode stack, a low specific contact resistance of 8.9 × 10{sup −6} Ω cm{sup 2} was achieved at an annealing temperature of 650 °C. Compared to the conventional Ti/Al/Ni/Au contact, this is a reduction of 150 K. The microstructure and contact formation at the AlGaN/metal interface were investigated by transmission electron microscopy including high-resolution micrographs and energy dispersive X-ray analysis. It was shown that for low-resistive contacts, the resistivity of the metalization has to be taken into account. The V:Al thickness ratio has an impact on the formation of different intermetallic phases and thus is crucial for establishing ohmic contacts at reduced annealing temperatures.},
doi = {10.1063/1.4907735},
journal = {Applied Physics Letters},
number = 5,
volume = 106,
place = {United States},
year = {Mon Feb 02 00:00:00 EST 2015},
month = {Mon Feb 02 00:00:00 EST 2015}
}