A physical finite difference model of a forward biased diode using SPICE

A physical model for the transient voltage drop of a forward biased diode with a lowly doped region is presented. The diffusion and transport equation is solved by the finite difference method in a spice simulator. The model is compared with VF-TLP measurement with different rise times of diodes with lowly doped regions of varying lengths. A good agreement of the transient voltage, notably the peak voltage and quasistatic voltage is achieved.