TY  - JOUR
PY  - 2004//
TI  - Rhenium ohmic contacts on 6H-SIC
JO  - Journal of applied physics
A1  - McDaniel, G.Y.
A1  - Fenstermaker, S.T.
A1  - Lampert, W.V.
A1  - Holloway, P.H.
SP  - 5357
EP  - 5364
VL  - 96
IS  - 9
N2  - Rhenium (Re) thin-film contacts (100-nm thick) were deposited on carbon-rich, nominally stoichiometric, and silicon-rich 6H-SiC surfaces, which were moderately doped with nitrogen (1.28×10 18 cm -3). Morphology (Dektak), phase formation (x-ray diffraction), chemistry (Auger electron spectroscopy), and electrical properties (I- V) were characterized for the as-deposited and annealed (120 min, 1000°C, vacuum <1 × 10 -6 Torr) contacts. As-deposited films were nonohmic. Films grown on carbon-rich surfaces were nonspecular, granular, and often delaminated during characterization. At room temperature in air, the Re films on stoichiometric SiC remained optically specular reflecting for 3 h, but then became hazy from oxidation. The Re films on silicon-rich surfaces, stored in air at room temperature, resisted ex situ oxidation for approximately 24 h. The annealed samples remained specular without visible signs of oxidation. The annealing resulted in a reduction in surface roughness for all the films regardless of substrate chemistry. The phase separation between carbon and rhenium was observed based on the formation of interfacial Re clusters and a ∼10-nm graphite surface layer after annealing. Auger data showed that Si layers (5-10 nm) deposited to create Si-rich surfaces were partially consumed to form rhenium suicide during annealing, and the sharp Re/Si/SiC interface became more diffused with Re detected ∼50 nm deeper into the structure. The annealing of Re films on moderately doped (1.28×10 18 cm -3) SiC resulted in ohmic contacts with an average specific contact resistance of 7.0×10 -5 ω cm 2 for stoichiometric and 1.6×10 -5 ω cm 2 for silicon-rich samples. The annealed contacts on carbon-rich surfaces remained rectifying. © 2004 American Institute of Physics.<p /> <p>Language: en</p>
LA  - en
SN  - 0021-8979
UR  - http://dx.doi.org/10.1063/1.1797550
ID  - ref1
ER  -