Investigation of barrier inhomogeneities in Mo/4H-SiC Schottky diodes

L. Boussouar, Z. Ouennoughi, N. Rouag, A. Sellai, R. Weiss, H. Ryssel

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Using current-voltage measurements, we have investigated the electrical behavior of molybdenum on 4H-SiC Schottky diodes of various areas and having different edge terminations consisting of high resistivity guard rings manufactured by carbon ion-implantation. Both forward and reverse electrical characteristics of Schottky contacts indicated a presence of inhomogeneities. The forward I-V characteristics have been primarily analyzed within the framework of a standard thermionic emission theory. Schottky-barrier heights and ideality factors are found to appreciably vary from diode to diode. A more general model which takes into account the inhomogeneity of the Schottky barrier has been then used to extract the parameters pertinent to the barrier height distribution. The description of the experimental results using Tung's model allowed us to determine the value of the average laterally homogeneous SBH barrier height between 1.2 and 1.39 eV for Mo/4H-SiC Schottky diodes. The patch's properties (the number of patches, the patch strength and the local series resistance) were also obtained from the fit to the experimental I-V characteristics of the current through "patchy" diodes. The obtained results are best described with this extended "pinch off" model. With respect to the reverse characteristics, the remarked absence of a non-saturating behavior as a function of bias in the experimental reverse-bias branch may well be attributed to the presence of defects and/or inhomogeneous Schottky barrier heights, associated with the non-ideal contacts.

Original languageEnglish
Pages (from-to)969-975
Number of pages7
JournalMicroelectronic Engineering
Volume88
Issue number6
DOIs
Publication statusPublished - Jun 2011

Fingerprint

Schottky diodes
Diodes
inhomogeneity
diodes
Thermionic emission
Molybdenum
thermionic emission
Voltage measurement
Electric current measurement
Ion implantation
electrical measurement
molybdenum
ion implantation
electric contacts
Carbon
Defects
electrical resistivity
carbon
rings
defects

Keywords

  • 4H-SiC
  • Barrier inhomogeneities
  • Current-voltage characteristics
  • Schottky diodes

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics

Cite this

Investigation of barrier inhomogeneities in Mo/4H-SiC Schottky diodes. / Boussouar, L.; Ouennoughi, Z.; Rouag, N.; Sellai, A.; Weiss, R.; Ryssel, H.

In: Microelectronic Engineering, Vol. 88, No. 6, 06.2011, p. 969-975.

Research output: Contribution to journalArticle

Boussouar, L, Ouennoughi, Z, Rouag, N, Sellai, A, Weiss, R & Ryssel, H 2011, 'Investigation of barrier inhomogeneities in Mo/4H-SiC Schottky diodes', Microelectronic Engineering, vol. 88, no. 6, pp. 969-975. https://doi.org/10.1016/j.mee.2010.12.070
Boussouar, L. ; Ouennoughi, Z. ; Rouag, N. ; Sellai, A. ; Weiss, R. ; Ryssel, H. / Investigation of barrier inhomogeneities in Mo/4H-SiC Schottky diodes. In: Microelectronic Engineering. 2011 ; Vol. 88, No. 6. pp. 969-975.
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AB - Using current-voltage measurements, we have investigated the electrical behavior of molybdenum on 4H-SiC Schottky diodes of various areas and having different edge terminations consisting of high resistivity guard rings manufactured by carbon ion-implantation. Both forward and reverse electrical characteristics of Schottky contacts indicated a presence of inhomogeneities. The forward I-V characteristics have been primarily analyzed within the framework of a standard thermionic emission theory. Schottky-barrier heights and ideality factors are found to appreciably vary from diode to diode. A more general model which takes into account the inhomogeneity of the Schottky barrier has been then used to extract the parameters pertinent to the barrier height distribution. The description of the experimental results using Tung's model allowed us to determine the value of the average laterally homogeneous SBH barrier height between 1.2 and 1.39 eV for Mo/4H-SiC Schottky diodes. The patch's properties (the number of patches, the patch strength and the local series resistance) were also obtained from the fit to the experimental I-V characteristics of the current through "patchy" diodes. The obtained results are best described with this extended "pinch off" model. With respect to the reverse characteristics, the remarked absence of a non-saturating behavior as a function of bias in the experimental reverse-bias branch may well be attributed to the presence of defects and/or inhomogeneous Schottky barrier heights, associated with the non-ideal contacts.

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