TY - JOUR
T1 - Formation of thermally stable low-resistance Ti/W/Au ohmic contacts on n-type GaN
AU - Reddy, V. R.
AU - Kim, S. H.
AU - Seong, T. Y.
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2005/8
Y1 - 2005/8
N2 - A Ti(12 nm)/W(20 nm)/Au(50 nm) metallization scheme has been investigated for obtaining thermally stable low-resistance ohmic contacts to n-type GaN (4.0×1018 cm-3). It is shown that the current-voltage (I-V) characteristics of the samples are abnormally dependent on the annealing temperature. For example, the samples that were annealed at temperatures below 750 °C for 1 min in a N2 ambient show rectifying behavior. However, annealing the samples at temperatures in excess of 850 °C results in linear I-V characteristics. The contact produces a specific contact resistance as low as 8.4×10-6 Ω∈cm2 when annealed at 900 °C. It is further shown that the contacts are fairly thermally stable even after annealing at 900 °C; annealing the samples at 900 °C for 30 min causes insignificant degradation of the electrical and structural properties. Based on glancing angle X-ray diffraction and Auger electron microscopy results, the abnormal temperature dependence of the ohmic behavior is described and discussed.
AB - A Ti(12 nm)/W(20 nm)/Au(50 nm) metallization scheme has been investigated for obtaining thermally stable low-resistance ohmic contacts to n-type GaN (4.0×1018 cm-3). It is shown that the current-voltage (I-V) characteristics of the samples are abnormally dependent on the annealing temperature. For example, the samples that were annealed at temperatures below 750 °C for 1 min in a N2 ambient show rectifying behavior. However, annealing the samples at temperatures in excess of 850 °C results in linear I-V characteristics. The contact produces a specific contact resistance as low as 8.4×10-6 Ω∈cm2 when annealed at 900 °C. It is further shown that the contacts are fairly thermally stable even after annealing at 900 °C; annealing the samples at 900 °C for 30 min causes insignificant degradation of the electrical and structural properties. Based on glancing angle X-ray diffraction and Auger electron microscopy results, the abnormal temperature dependence of the ohmic behavior is described and discussed.
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U2 - 10.1007/s00339-004-2673-3
DO - 10.1007/s00339-004-2673-3
M3 - Article
AN - SCOPUS:21644482411
VL - 81
SP - 561
EP - 564
JO - Applied Physics A: Materials Science and Processing
JF - Applied Physics A: Materials Science and Processing
SN - 0947-8396
IS - 3
ER -