Interface Trap-Induced Nonideality in As-Deposited Ni/4H-SiC Schottky Barrier Diode

As-deposited Ni/SiC Schottky diodes often show nonideal forward conduction characteristics. The ideality can be improved by the formation of a nickel-silicide/SiC interface by annealing at 650 °C. The nonideal characteristics in as-deposited diodes are generally attributed to Schottky barrier inhomogeneity at the interface. However, recent studies show that highly nonideal characteristics (n 1.2) cannot be explained by the existing inhomogeneity models. In this paper, we report the observation of hysteresis patterns in the I-V and CV characteristics of as-deposited nonideal diodes. It is argued that the existence of evenly distributed slow, donor-like interface traps can explain the hysteresis and the associated Schottky nonideality. A trap density of 10⁸-10¹⁰ cm^-2 was estimated from the I-V and CV hysteresis.