Avalanche Breakdown in the Base-Emitter- Shorted Silicon Avalanche Transistor Affected by Voltage Ramp

This article discusses the ultrafast switching of the dc-biased avalanche bipolar junction transistor (ABJT) with short-connected base and emitter, utilizing the trigger of a fast voltage ramp through the device. Applying by the fast dV/dt ramp, the transistor switched on due to powerful avalanche ionization. It was found that the switching properties and mechanisms were much different by varying dV/dt ramps. Therefore, we constructed a testing circuit to investigate the characteristics of the individual ABJT. When the rise time of the ramp decreased from 2.2 ns to 181 ps, the rise time of the output pulse decreased from 1.3 ns to 156 ps, respectively, in our experiments. The switching transients were analyzed featuring typical dV/dt ramps with risetimes of 2.2 ns and 181 ps, respectively. The results of 2-D simulations showed good agreements with experimental voltage curves in the ABJT. Moreover, the switching characteristics affected by the voltage ramps were also discussed numerically.