Small-signal impedance of space-charge-limited semiconductor diodes

A generalised expression for the small-signal impedance of semiconductor diodes with unipolar space-charge-limited (s.c.l.) current is presented. The field dependence of carrier mobility, as well as ionised impurities (or deep traps), is taken into account. As long as the diffusion current can be neglected, these results appear to cover almost all cases of practical interest for Si, Ge or GaAs s.c.l. diodes.