Generation-recombination noise in forward biased 4H-SiC p-n diodes

Abstract

Low frequency noise has been studied in forward biased 4H-SiC p+-n diodes at current densities from 10−4to10A∕cm2. At small current densities j⩽10−3A∕cm2, the spectral noise density SI follows the law SI∝1∕f3∕2. At 10−3A∕cm2 <j<10−2A∕cm2, the generation-recombination (GR) noise predominates. The amplitude of this GR noise nonmonotonically depends on current. At j⩾10−2A∕cm2, the 1∕f (flicker noise) dominates. It has been shown that the recombination time in the space charge region of the p+-n junction, τR, is about 70ns. This value is approximately one order of magnitude larger than that reported earlier for SiC p-n structures. A model of GR noise in forward biased p-n junctions has been proposed. The model links the GR noise with fluctuations of the charge state of a trap in the space charge region.