High-power punch-through avalanche-diode microwave oscillators

Two distinctive modes of oscillation are observed in specially profiled silicon avalanche diodes: transit-time mode at 3 to 7 GHz at lower bias current densities and an anomalous mode at around 1 GHz above certain threshold current levels. High pulsed power has been produced from both modes of operation. Space-charge-induced negative resistances are computed and their dependence on device parameters are discussed. Experimentally observed correlations between these two modes, including a locking behavior of the anomalous mode by the transit-time mode, and the computed and observed slight negative resistance at the anomalous-mode threshold suggest that the transit- time-mode oscillation and the space-charge-induced negative resistance are two possible pre-requisites for the initiation of the anomalous mode of oscillation.