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

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

Research output: Contribution to journalArticle

19 Scopus citations

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 - Apr 1998

All Science Journal Classification (ASJC) codes

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

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