Investigation of ultralow leakage in MOS capacitors on 4H SiC

Ultralow leakage current through nitrided gate oxides on 4H SiC is investigated by a novel technique in this paper. The technique utilizes capacitance-voltage (C-V) measurements to characterize the relaxation of nonequilibrium capacitance due to charge leakage in floating-gate metal-oxide-semiconductor capacitors. The C-V measurements are performed at elevated temperatures and the results are extrapolated to room temperature. The obtained values for the relaxation times are in the order of 10¹³ s for MOS capacitors on both n-type and p-type 4H SiC.