On The Schottky Barrier Height Lowering Effect of Ti3SiC2 in Ohmic Contacts to P-Type 4H-SiC

Nanophysics

Authors

  • C. A. Fisher School of Engineering, University of Warwick, Coventry, CV4 7AL, UK
  • M. R. Jennings School of Engineering, University of Warwick, Coventry, CV4 7AL, UK
  • Y. K. Sharma School of Engineering, University of Warwick, Coventry, CV4 7AL, UK
  • A. Sanchez-Fuentes Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
  • D. Walker Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
  • P. M. Gammon School of Engineering, University of Warwick, Coventry, CV4 7AL, UK
  • A. Pérez-Tomás Institut Català De Nanociència i Nanotecnologia, 08193, Bellaterra, Spain
  • S. M. Thomas School of Engineering, University of Warwick, Coventry, CV4 7AL, UK

DOI:

https://doi.org/10.14331/ijfps.2014.330071

Keywords:

4H-SiC, ohmic contact, p-type, Ti3SiC2

Abstract

In this paper, an experimental investigation into titanium (Ti) / aluminium (Al)-based ohmic contacts to p-type 4H-silicon carbide (SiC) has been presented. Electrical characterisation of the fabricated contacts showed that metal structures with an initial Ti layer yielded the lowest specific contact resistance (ρc), with a mean value of 3.7×10-5 Ω-cm2 being achieved after annealing in argon (Ar) at 1000°C for 2 minutes. Transmission electron microscopy (TEM) analysis illustrated the epitaxial relationship between the 4H-SiC and the as-deposited Ti layer, and, in conjunction with energy dispersive X-ray (EDX) analysis, showed that after annealing a ~5 nm thick layer of Ti3SiC2 was present, epitaxially arranged with the 4H-SiC. X-ray diffraction (XRD) analysis showed that the presence of the Ti3SiC2 metallic phase was more prevalent in the samples with Ti as the initial metal layer annealed at 1000°C, which corresponded with lower specific contact resistance. Fitting of experimental data to a thermionic field emission (TFE) model allowed the Schottky barrier height to be extracted; it was found that the lowest Schottky barrier heights were more prevalent where the most intense Ti3SiC2 phases were observed during XRD analysis.

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References

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Published

2014-09-30

Issue

Vol. 4 No. 3 (2014): IJFPS

Section

ORIGINAL ARTICLES

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