Capacitance-conductance spectroscopic investigation of interfacial oxide layer in Ni/4H-SiC (0001) Schottky diode

In this reported work the interface properties of a process-induced thin interfacial oxide layer present between Ni and 4H-SiC substrate was examined systematically for fabricated Ni/4H-SiC (0 0 0 1) Schottky barrier diodes. Moreover, their contribution in the form of interface traps level density was investigated employing capacitance-conductance (C-C) spectroscopy techniques. The distinctive parameters of interface at Ni and 4H-SiC substrate were determined from the C-C spectroscopy under forward bias condition. The increase in capacitance value towards lower frequencies results from the presence of interface traps at the Ni/4H-SiC interface however the observed maximums peaks in the normalized conductance curve of the diode indicates the presence of an interfacial layer in the fabricated Schottky barrier diode. It has been found that the density of interface traps level decreases (1.25 x 10(13)-1.16 x 10(13) cm(-2) eV(-1)) and time constant of interface traps (3.16 x 10(-5) -1.47 x 10(-3) s) increases with bias voltage at anode in the range of Ec-0.06 to Ec-1.06 eV from the top of conduction band toward midgap of n-type 4H-SiC substrate. Furthermore, the capture cross section was found to vary from 9.31 x 10(-10) cm(2) in (E-c-0.06) eV to 443 x 10(-11) cm(2) in (E-c-1.06) eV. (C) 2013 Elsevier B.V. All rights reserved