Barrier inhomogeneities of tungsten Schottky diodes on 4H-SiC

Electrical properties of tungsten on silicon carbide (4H-SiC) Schottky diodes are investigated through the analysis of the forward current-voltage (I-V) characteristics measured at elevated temperatures within the range of 303-448 K. The subsequently derived Schottky barrier heights (SBHs) and ideality factors are found to be temperature dependent with distributions that are adequately explained within the framework of the model proposed by Tung in which he considers the barrier at a metal-semiconductor interface as consisting of locally non-uniform but interacting patches of different barrier heights embedded in a background of uniform barrier height. A uniform barrier height of 1.248 eV, a Richardson's constant of 129.95 A cm^-2 K² and a factor T_o of 23.92 K obtained agree very well with values published previously for similar Schottky barrier systems. Therefore, it has been concluded that the temperature-dependent I-V characteristics of the device can be successfully explained with lateral inhomogeneities distribution of the SBH.