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Title: Rhenium ohmic contacts on 6H-SiC

Abstract

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 (1.28x10{sup 18} cm{sup -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 deg. C, vacuum <1x10{sup -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 {approx}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 silicide during annealing, and the sharp Re/Si/SiC interface became more diffusedmore » with Re detected {approx}50 nm deeper into the structure. The annealing of Re films on moderately doped (1.28x10{sup 18} cm{sup -3}) SiC resulted in ohmic contacts with an average specific contact resistance of 7.0x10{sup -5} {omega} cm{sup 2} for stoichiometric and 1.6x10{sup -5} {omega} cm{sup 2} for silicon-rich samples. The annealed contacts on carbon-rich surfaces remained rectifying.« less

Authors:
; ; ;  [1];  [2];  [2];  [2]
  1. Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611-6400 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20662160
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 96; Journal Issue: 9; Other Information: DOI: 10.1063/1.1797550; (c) 2004 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANNEALING; AUGER ELECTRON SPECTROSCOPY; DEPOSITION; DOPED MATERIALS; ELECTRICAL PROPERTIES; ELECTRON BEAMS; GRAPHITE; INTERFACES; MORPHOLOGY; NITROGEN; OXIDATION; RHENIUM; ROUGHNESS; SEMICONDUCTOR MATERIALS; SILICON CARBIDES; STOICHIOMETRY; SUBSTRATES; TEMPERATURE RANGE 0273-0400 K; THIN FILMS; X-RAY DIFFRACTION

Citation Formats

McDaniel, G.Y., Fenstermaker, S.T., Lampert, W.V., Holloway, P.H., and Air Force Reasearch Laboratory/Materials and Manufacturing Dictorate, Wright Patterson Air Force Base, Ohio, 45433-7707, Air Force Research Laboratory/Materials and Manufacturing Directorate, Wright Patterson Air Force Base, Ohio 45433-7707, and Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611-6400. Rhenium ohmic contacts on 6H-SiC. United States: N. p., 2004. Web. doi:10.1063/1.1797550.
McDaniel, G.Y., Fenstermaker, S.T., Lampert, W.V., Holloway, P.H., and Air Force Reasearch Laboratory/Materials and Manufacturing Dictorate, Wright Patterson Air Force Base, Ohio, 45433-7707, Air Force Research Laboratory/Materials and Manufacturing Directorate, Wright Patterson Air Force Base, Ohio 45433-7707, & Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611-6400. Rhenium ohmic contacts on 6H-SiC. United States. doi:10.1063/1.1797550.
McDaniel, G.Y., Fenstermaker, S.T., Lampert, W.V., Holloway, P.H., and Air Force Reasearch Laboratory/Materials and Manufacturing Dictorate, Wright Patterson Air Force Base, Ohio, 45433-7707, Air Force Research Laboratory/Materials and Manufacturing Directorate, Wright Patterson Air Force Base, Ohio 45433-7707, and Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611-6400. Mon . "Rhenium ohmic contacts on 6H-SiC". United States. doi:10.1063/1.1797550.
@article{osti_20662160,
title = {Rhenium ohmic contacts on 6H-SiC},
author = {McDaniel, G.Y. and Fenstermaker, S.T. and Lampert, W.V. and Holloway, P.H. and and Air Force Reasearch Laboratory/Materials and Manufacturing Dictorate, Wright Patterson Air Force Base, Ohio, 45433-7707 and Air Force Research Laboratory/Materials and Manufacturing Directorate, Wright Patterson Air Force Base, Ohio 45433-7707 and Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611-6400},
abstractNote = {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 (1.28x10{sup 18} cm{sup -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 deg. C, vacuum <1x10{sup -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 {approx}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 silicide during annealing, and the sharp Re/Si/SiC interface became more diffused with Re detected {approx}50 nm deeper into the structure. The annealing of Re films on moderately doped (1.28x10{sup 18} cm{sup -3}) SiC resulted in ohmic contacts with an average specific contact resistance of 7.0x10{sup -5} {omega} cm{sup 2} for stoichiometric and 1.6x10{sup -5} {omega} cm{sup 2} for silicon-rich samples. The annealed contacts on carbon-rich surfaces remained rectifying.},
doi = {10.1063/1.1797550},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 9,
volume = 96,
place = {United States},
year = {2004},
month = {11}
}