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

Gaussförmige Verteilung von Inhomogenitäten bei Wolfram/4H-CiC (000`1) Schottky-Dioden
: Toumi, S.; Ferhat-Hamida, A.; Boussouar, L.; Sellai, A.; Ouennoughi, Z.; Ryssel, H.


Microelectronic engineering 86 (2009), Nr.3, S.303-309
ISSN: 0167-9317
International Symposium on Advanced Gate Stack Technology (ISAGST) <4, 2007, Dallas/Tex.>
Zeitschriftenaufsatz, Konferenzbeitrag
Fraunhofer IISB ()
electrical measurement; Schottky barrier; silicon carbide; tungsten; inhomogeneity

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 IV characteristics measured at elevated temperatures within the range of 303448 K and by the assumption of a Gaussian distribution (GD) of barrier heights (BHs), a mean barrier height image 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 image 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 IV 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.