Refractory metal boride ohmic contacts to P-Type 6H-SiC

T. N. Oder, J. R. Williams, S. E. Mohney, J. Crofton

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

Ohmic contacts have been fabricated on p-type 6H-SiC (1.3 × 1019 cm-3) using CrB2, W2B, and TiB2. The boride layers (∼100-200 nm) were sputter-deposited 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. All as-deposited contacts exhibited rectifying characteristics. Ohmic behavior was observed following short anneals (2-10 min) at 1100°C and 5 × 10-7 Torr. Current-voltage characteristics were linear for CrB2 and W2B and quasi-linear for TiB2. The lowest values of the specific contact resistance (rc in Ω-cm2) measured at room temperature for CrB2 and W2B were 8.2 × 10-5 and 5.8 × 10-5 respectively. The specific contact resistance for TiB2 was not determined accurately. Longer anneals (30 min for W2B and 90 min for CrB2) reduced the room temperature values of rc to 6.1 × 10-5 for W2B and 1.9 × 10-5 for CrB2. Backscattering spectra revealed substantial concentrations of oxygen in all as-deposited boride films. The short anneal cycle removed the oxygen in the CrB2 films and reduced the concentration substantially in the W2B films; however, annealing had no affect on the oxygen concentration in the TiB2 films. The CrB2/SiC interface remained stable during annealing; i.e., Si and carbon were not observed in the boride layers after annealing. In contrast, W2B and TiB2 reacted with the SiC epilayers, and after annealing, Si and carbon were observed at the surface of each boride layer.

Original languageEnglish (US)
Pages (from-to)12-16
Number of pages5
JournalJournal of Electronic Materials
Volume27
Issue number1
DOIs
StatePublished - Jan 1998

All Science Journal Classification (ASJC) codes

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

Fingerprint Dive into the research topics of 'Refractory metal boride ohmic contacts to P-Type 6H-SiC'. Together they form a unique fingerprint.

  • Cite this