A Self-Consistent Model of the OCVD Behavior of Si and 4H-SiC p+-n-n+ Diodes

A comprehensive analytical model of the open-circuit voltage-decay (OCVD) response for a generic diode, switched from an arbitrary forward-bias condition, is proposed. To properly account for the steady-state conditions of the diode, the dynamic model incorporates an accurate description of the static I-V curves, which turns also useful for better understanding the influence of physical parameters on voltage transitory. As shown from comparisons with simulations and experiments, the model accurately describes the spatial-temporal variation of carriers and currents along the whole epilayer and allows one to resolve some ambiguities reported in the literature, such as the stated inapplicability of the OCVD method on thick epilayers, the reasons of the observed nonlinear decay of the voltage with time, and the effects of junction properties on voltage transient.