Electrical analysis and interface states evaluation of Ni Schottky diodes on 4H-SiC thick epilayers

This work has been focused on characterization of thick 4H-SiC layers produced by sublimation epitaxy. Nickel Schottky contacts have been fabricated in order to characterize the grown material and evaluate the interfacial layer between metal and semiconductor. The characterization study includes current-voltage and capacitance-voltage high temperature measurements, from which Schottky barrier, net donor concentration and on-state resistance values have been extracted. The diodes show a typical behavior of J-V and C-V curves with temperature, with Schottky barrier heights of 1.3 eV divided by 1.4 eV and net donor concentration of 4 x 10(15) cm(-3) divided by 1 x 10(16) cm(-3). From the Bardeen's model on reverse J-V, the density of states of the interfacial layer has been estimated to 7 x 10(11) eV(-1) cm(-2) divided by 8 x 10(11) eV(-1) cm, a value that is similar to the density of states of oxide layers in deliberated MOS structures realized on the same epilayers. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.