Superfast high-current switching of GaAs avalanche transistor

Ultrahigh field multiple Gunn domains as the physical reason for superfast (picosecond range) switching of a bipolar GaAs transistor

“…Furthermore, the device area used in the simulations was fitted to the experimental data on current filamentation. 5 In this experiment a number of light-emitting channels were observed along the perimeter of the emitter-base interface in a single transistor switching. These channels had a more or less random spatial distribution, with their locations varying from one current pulse to another.…”

“…5 This provides unique turn-on parameters not achievable with any active commercial semiconductor component available at present. The time required for the reduction in collector voltage from the initial biasing of ϳ300 V to a value of ϳ90-100 V was shorter by a factor of ϳ15 than that in Si avalanche transistors, and an order of magnitude shorter than that predicted by the driftdiffusion model for a Si-like shape of the electron velocity versus electric field dependence.…”

Investigation on properties of ultrafast switching in a bulk gallium arsenide avalanche semiconductor switch

“…5,6 However, generation of the dV/dt ramp is extremely difficult and the circuit is fairly complicated. 7 The sub-nanosecond switching mode has been observed in GaAs switches, for example, GaAs thyristor, 8 bipolar GaAs transistor, 9 and photoconductive switch (PCSS). [10][11][12] The GaAs junction devices have voltage limits associated with their background doping and thickness, while PCSS can be made as long as desired in principle and can hold higher voltage than the junction device.…”

“…22 The life time and repetition rate of PCSS are limited, since the filamentary nature of the current causes failures, including degradation at the metal-semiconductor interface, breakdown, and surface flashover. 23 A number of light-emitting channels have been observed in a bulk GaAs transistor, 9 which is beneficial to improve performance of GaAs avalanche switch with bulk structure. Bulk GaAs avalanche semiconductor switch exhibits obviously advantages in longevity and high repetition rate comparing with an opposed contact PCSS.…”

Negative differential mobility in GaAs at ultrahigh fields: Comparison between an experiment and simulations

“…5 and 6͒ from E ഛ 0.2 toward E ϳ 0.6 MV/ cm was used in the simulations. Proof of the collapsing domains concept would be fairly important not only for superfast switching 12 but also for a convincing interpretation of the nature of the copious terahertz and "hot" photon emission observed from a GaAs BJT structure. 14 Verification of the existence of NDM at very high electric fields is especially important in view of the contradicting predictions of Monte Carlo simulations, 11 which claim violation of NDM at E ജ 0.33 MV/ cm due to population of the X 7 valley in the second conduction band.…”