Gaussian distribution of inhomogeneous barrier height in tungsten/4H-SiC (000-1) Schottky diodes

S. Toumi, A. Ferhat-Hamida, L. Boussouar, A. Sellai, Z. Ouennoughi, H. Ryssel

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34 Citations (Scopus)

Abstract

The Gaussian distribution model have been used to analyze the anomalies observed in tungsten (W)/4H-SiC current voltage characteristics due to the barrier inhomogeneities that prevail at the metal-semiconductor interface. From the analysis of the forward I-V characteristics measured at elevated temperatures within the range of 303-448 K and by the assumption of a Gaussian distribution (GD) of barrier heights (BHs), a mean barrier height over(Φ, ̄)B 0 of 1.277 eV, a zero-bias standard deviation σ0 = 0.092 V and a factor T0 of 21.69 K have been obtained. Furthermore the modified Richardson plot according to the Gaussian distribution model resulted in a mean barrier height over(Φ, ̄)B 0 and a Richardson constant (A*) of 1.276 eV and 145 A/cm2 K2, respectively. The A* value obtained from this plot is in very close agreement with the theoretical value of 146 A/cm2 K2 for n-type 4H-SiC. Therefore, it has been concluded that the temperature dependence of the forward I-V characteristics of the W/4H-SiC contacts can be successfully explained on the basis of a thermionic emission conduction mechanism with Gaussian distributed barriers. In addition, a comparison is made between the present results and those obtained previously assuming the pinch-off model.

Original languageEnglish
Pages (from-to)303-309
Number of pages7
JournalMicroelectronic Engineering
Volume86
Issue number3
DOIs
Publication statusPublished - Mar 2009

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Keywords

  • Electrical measurements
  • Inhomogeneity
  • Schottky barrier
  • Silicon carbide
  • Tungsten

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

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