Large-signal theory for rectangular-voltage operation of a uniform avalanche zone in IMPATT diodes

Explicit solutions are derived for the currents in a lightly doped high-field zone of an IMPATT diode subject to constant E field avalanche. Resulting particle-current waveforms, diode impedances and r.f. powers are calculated for Si and GaAs with the avalanche period followed by a sudden transition to a low-voltage carrier-extraction period. It is concluded that the addition of a drift zone will only ease impedance matching and enhance efficiency when differences of either ionisation rates or drift velocities between electrons and holes exist.