Current-conduction mechanism in Au/n-4H-SiC Schottky barrier diodes
Au/n-4H-SiC Schottky barrier diodes (SBDs) were fabricated and their temperature and voltage dependence of saturation current (Io), ideality factor (n), barrier height (Φbo), series and shunt resistances (Rs, Rsh) values were obtained by using current-voltage (I-V) measurements in the temperature range 110-400 K. The values of Io, n and Φbo were found as 3.00 10-14A, 3.41 and 0.39 eV at 110 K and 7.7510-7A, 1.64 and 0.90 eV at 400 K, respectively. The Φbo-q/2kT plot was drawn to obtain an evidence of a Gaussian distribution (GD) of the barrier heights (BHs). The mean BH (Φbo) and standard deviation (σo) values have been extracted from the intercept and slope of this plot is as 1.089 eV and 0.127 V, respectively. The Φbo and Richardson constant (A*) values were obtained from the modified Ln(Io/T2)-(q2σs2/2k2T2) versus q/kT plot as 1.093 eV and 160.6 A.cm-2K-2 which can be considered as close to the theoretical value 146 A.cm-2K-2, respectively. Voltage dependent activation energy (Ea) value was also obtained from the In(Io/T2)-q/kT and In(Io/T2)-q/nkT plots in the voltage range 0.05-0.50 V with 0.05 V steps and it is found that it decreases with increasing voltage. The temperature dependence of I-V characteristics in Au/n-4H-SiC diodes can be successfully explained on the basis of a TE mechanism with GD of the BHs.
Au/n-4H-SiC diodes; Temperature dependent BH and ideality factor; Barrier inhomogeneities; Gaussien distrubition
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