Analyses of the Picosecond Range Transient in a High-Power Switch Based on a Bipolar GaAs Transistor Structure

Terahertz Emission from Collapsing Field Domains during Switching of a Gallium Arsenide Bipolar Transistor

“…Relatively weak impact ionization in Gunn domains may complicate the effect due to presence of holes, and cause current filamentation [2,3]. Powerfully ionizing multiple domains with very unusual parameters and temporal evolution were recently predicted in transient simulations of superfast switching in an n -p-n 0 -n transistor structure in which copious electron injection takes place into a high-voltage biased (depleted) layer of n-type gallium arsenide [4,5]. Current filamentation is intrinsic to this regime [4].…”

“…Only one item of experimental evidence for the existence of collapsing domains has been found so far, namely, a good fit [5] between simulated and measured voltage and current waveforms during the switching transient in a GaAs BJT. We present here some additional arguments, namely, experimentally observed terahertz emission and ''hot'' photon emission during the switching of a GaAs BJT.…”

“…The part of the numerical model describing carrier transport and impact ionization was analogous to that in Refs. [4,5]; the switching current passed across several channels (total area 3:7 10 ÿ6 cm 2 ) and fast growth in carrier density in the channels was brought about by powerful impact ionization in multiple (collapsing) field domains spreading along the filaments. The simulated current in the channels [curve 3 0 in the inset to Fig.…”

“…The simulated current in the channels [curve 3 0 in the inset to Fig. 1(a)] demonstrated powerful picosecond-range oscillations, which did not penetrate to the external circuit (curve 2 0 ) but became locked within the barrier capacitance of the nonswitched part of the transistor structure [5].…”

Comparison of the leading-edge timing walk in pulsed TOF laser range finding with avalanche bipolar junction transistor (BJT) and metal-oxide-semiconductor (MOS) switch based laser diode drivers

“…The switching of an avalanche transistor is a rather complicated 2D phenomenon and has been quite extensively studied in the literature. [19][20][21][22][23][24] From the practical point of view, an avalanche transistor is an NPN bipolar junction transistor (BJT), whose collector is biased above the collector-base pn-junction breakdown limit. When its base-emitter circuit is driven with a proper triggering signal, a high-speed breakdown occurs, resulting in a steplike change in the collector voltage from the bias voltage V HV to a residual voltage typically of a few tens of volts.…”