High temperature stability of chromium boride ohmic contacts to p-type 6H-SiC

T. N. Oder, J. R. Williams, M. J. Bozack, V. Iyer, Suzanne E. Mohney, J. Crofton

Research output: Contribution to journalArticle

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Abstract

Ohmic contacts have been fabricated on p-type 6H-SiC using CrB2. Two hundred nanometer thick films were sputter-deposited on substrates of doping concentration 1.3 × 1019 cm-3 in a system with a base pressure of 3 × 10-7 Torr. Specific contact resistances were measured using the linear transmission line method, and the physical properties of the contacts were examined using Rutherford backscattering spectrometry, x-ray photoelectron spectroscopy, and transmission electron microscopy. The as-deposited CrB2 contacts exhibited rectifying characteristics and contained oxygen as a major contaminant. Ohmic behavior with linear current-voltage characteristics was observed following short anneals at 1100°C for 2 min at a pressure of 5 × 10-7 Torr. The oxygen in the CrB2 films was removed by the annealing process, and the lowest value of the specific contact resistance (rc) measured at room temperature was 8.2 × 10-5 Ω-cm2. Longer anneals at 1100°C for 3.5 h and 1200°C for 2 h reduced the room temperature values of rc to 1.4 × 10-5 Ω-cm2. A thin reaction region has been identified at the CrB2/SiC interface; however, the interface remains essentially stable. Thermal stressing at 300°C in vacuum for over 2200 h produced only a slight increase in the specific contact resistance. The low value of the specific contact resistance and the excellent high temperature stability of the CrB2/SiC interface make this contact a candidate for high power/high temperature SiC device applications.

Original languageEnglish (US)
Pages (from-to)324-329
Number of pages6
JournalJournal of Electronic Materials
Volume27
Issue number4
DOIs
StatePublished - Jan 1 1998

Fingerprint

chromium borides
Boron Compounds
Borides
Ohmic contacts
Chromium
Contact resistance
contact resistance
electric contacts
Oxygen
base pressure
Temperature
Rutherford backscattering spectroscopy
room temperature
oxygen
Current voltage characteristics
Photoelectron spectroscopy
Thick films
Spectrometry
x ray spectroscopy
transmission lines

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

Cite this

Oder, T. N. ; Williams, J. R. ; Bozack, M. J. ; Iyer, V. ; Mohney, Suzanne E. ; Crofton, J. / High temperature stability of chromium boride ohmic contacts to p-type 6H-SiC. In: Journal of Electronic Materials. 1998 ; Vol. 27, No. 4. pp. 324-329.
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High temperature stability of chromium boride ohmic contacts to p-type 6H-SiC. / Oder, T. N.; Williams, J. R.; Bozack, M. J.; Iyer, V.; Mohney, Suzanne E.; Crofton, J.

In: Journal of Electronic Materials, Vol. 27, No. 4, 01.01.1998, p. 324-329.

Research output: Contribution to journalArticle

TY - JOUR

T1 - High temperature stability of chromium boride ohmic contacts to p-type 6H-SiC

AU - Oder, T. N.

AU - Williams, J. R.

AU - Bozack, M. J.

AU - Iyer, V.

AU - Mohney, Suzanne E.

AU - Crofton, J.

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N2 - Ohmic contacts have been fabricated on p-type 6H-SiC using CrB2. Two hundred nanometer thick films were sputter-deposited on substrates of doping concentration 1.3 × 1019 cm-3 in a system with a base pressure of 3 × 10-7 Torr. Specific contact resistances were measured using the linear transmission line method, and the physical properties of the contacts were examined using Rutherford backscattering spectrometry, x-ray photoelectron spectroscopy, and transmission electron microscopy. The as-deposited CrB2 contacts exhibited rectifying characteristics and contained oxygen as a major contaminant. Ohmic behavior with linear current-voltage characteristics was observed following short anneals at 1100°C for 2 min at a pressure of 5 × 10-7 Torr. The oxygen in the CrB2 films was removed by the annealing process, and the lowest value of the specific contact resistance (rc) measured at room temperature was 8.2 × 10-5 Ω-cm2. Longer anneals at 1100°C for 3.5 h and 1200°C for 2 h reduced the room temperature values of rc to 1.4 × 10-5 Ω-cm2. A thin reaction region has been identified at the CrB2/SiC interface; however, the interface remains essentially stable. Thermal stressing at 300°C in vacuum for over 2200 h produced only a slight increase in the specific contact resistance. The low value of the specific contact resistance and the excellent high temperature stability of the CrB2/SiC interface make this contact a candidate for high power/high temperature SiC device applications.

AB - Ohmic contacts have been fabricated on p-type 6H-SiC using CrB2. Two hundred nanometer thick films were sputter-deposited on substrates of doping concentration 1.3 × 1019 cm-3 in a system with a base pressure of 3 × 10-7 Torr. Specific contact resistances were measured using the linear transmission line method, and the physical properties of the contacts were examined using Rutherford backscattering spectrometry, x-ray photoelectron spectroscopy, and transmission electron microscopy. The as-deposited CrB2 contacts exhibited rectifying characteristics and contained oxygen as a major contaminant. Ohmic behavior with linear current-voltage characteristics was observed following short anneals at 1100°C for 2 min at a pressure of 5 × 10-7 Torr. The oxygen in the CrB2 films was removed by the annealing process, and the lowest value of the specific contact resistance (rc) measured at room temperature was 8.2 × 10-5 Ω-cm2. Longer anneals at 1100°C for 3.5 h and 1200°C for 2 h reduced the room temperature values of rc to 1.4 × 10-5 Ω-cm2. A thin reaction region has been identified at the CrB2/SiC interface; however, the interface remains essentially stable. Thermal stressing at 300°C in vacuum for over 2200 h produced only a slight increase in the specific contact resistance. The low value of the specific contact resistance and the excellent high temperature stability of the CrB2/SiC interface make this contact a candidate for high power/high temperature SiC device applications.

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