TY - JOUR
T1 - Ohmic contact formation mechanism of Ta/Al/Mo/Au and Ti/Al/Mo/Au metallizations on Al/GaN/GaN HEMTs
AU - Mohammed, Fitih M.
AU - Wang, Liang
AU - Selvanathan, Deepak
AU - Hu, Hubert
AU - Adesida, Ilesanmi
N1 - Funding Information:
The work at the University of Illinois was supported by ONR Grants No. N00014-01-1-1000 and No. N00014-01-1-1072 (Monitor: Dr. H. Dietrich). AES, XRD, (S)TEM, and AFM measurements were carried out in the Center for Microanalysis of Materials, University of Illinois, which is partially supported by the U.S. Department of Energy under Grant No. DEFG02-91-ER45439.
PY - 2005/11
Y1 - 2005/11
N2 - A comparative study of TaAlMoAu and TiAlMoAu metallizations for AlGaNGaN high electron mobility transistors is presented. By the optimization of surface treatment schemes and annealing temperature, contact resistances of 0.172 and 0.228 Ω mm, and specific contact resistivities of 2.96× 10-7 and 1.09× 10-6 Ω cm2 were obtained for TiAlMoAu and TaAlMoAu, respectively. Auger electron spectroscopy (AES), x-ray diffraction (XRD), and transmission electron microscopy (TEM) were utilized to study microstructural changes occurring in the metallization layers as a result of heat treatment. Results indicate dynamic systems of severe intermixing between atoms from the metallization layers and epilayers resulting in changes in surface morphology, as determined by atomic force microscopy (AFM). The formation of intermetallics and interfacial compounds was observed. The combined effect of surface treatment and annealing-induced reaction is proposed as the mechanisms for low-resistance Ohmic contact formation.
AB - A comparative study of TaAlMoAu and TiAlMoAu metallizations for AlGaNGaN high electron mobility transistors is presented. By the optimization of surface treatment schemes and annealing temperature, contact resistances of 0.172 and 0.228 Ω mm, and specific contact resistivities of 2.96× 10-7 and 1.09× 10-6 Ω cm2 were obtained for TiAlMoAu and TaAlMoAu, respectively. Auger electron spectroscopy (AES), x-ray diffraction (XRD), and transmission electron microscopy (TEM) were utilized to study microstructural changes occurring in the metallization layers as a result of heat treatment. Results indicate dynamic systems of severe intermixing between atoms from the metallization layers and epilayers resulting in changes in surface morphology, as determined by atomic force microscopy (AFM). The formation of intermetallics and interfacial compounds was observed. The combined effect of surface treatment and annealing-induced reaction is proposed as the mechanisms for low-resistance Ohmic contact formation.
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U2 - 10.1116/1.2101691
DO - 10.1116/1.2101691
M3 - Article
AN - SCOPUS:29044440928
VL - 23
SP - 2330
EP - 2335
JO - Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
JF - Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
SN - 1071-1023
IS - 6
ER -