Collapsing Gunn Domains as a Mechanism of Self-Supporting Conducting State in Reversely Biased High-Voltage GaAs Diodes

Switching of a high-voltage GaAs diode to the conducting state in the delayed impact-ionization mode is simulated and the results are compared with experimental data. It is shown that the effect of long-term (up to 100 ns) sustaining of the conducting state of the diode after switching is due to the appearance of narrow (of the order of a micrometer) ionizing Gunn domains, the so-called collapsing domains, in the electron-hole plasma. Impact ionization in collapsing domains and in the edge (cathode and anode) domains of a strong electric field (~300 kV/cm) maintains a high concentration of nonequilibrium carriers (≥10 17 cm –3 ) during the entire duration of the applied reverse polarity voltage pulse.