Time-dependent model of an optically triggered GaAs switch

Abstract

A numerical model for optically triggered switching in bulk GaAs is presented. First, a one-dimensional model is described and calculated behavior compared to experimental observations. Results from the one-dimensional model are not consistent with observed switching behavior. The model is then modified to include filament formation. Results from the modified model agree qualitatively and quantitatively with experimental data. Details of the dynamic behavior of the device are shown and a unified picture of the switching phenomenon presented. On the basis of the agreement of the numerical model and experimental observation it is concluded that switching is a result of localized impact ionization creating a conductive filament channel through the bulk material.

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

“…13 In this mode, PCSS switches and remains in turn-on state for hundreds nanoseconds after the laser turns off, and a current flows through a filament with as high current density as several MA/cm 2 . 14,15 There are several theories explaining the phenomena in PCSS with consideration of intrinsic impact ionization, 16 deep impurity ionization, 17 collect ionization, 18 double injection, 19 streamer formation, 20 recombination radiation, 21 and photoactivated charge domain. 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.…”

Modeling of high power semiconductor switches operated in the nonlinear mode

“…10,11 These models have recognized different mechanisms as being important in explaining lock-on and filament formation. These mechanisms include avalanche, 12 electric field dependent trap filling, 13 metastable impact ionization, 14 localized impact ionization, 15 and double-injection and carrier trapping. 16 In this work, a previously developed model 17 to investigate GaAs͑Si:Cu͒ PCSS has been applied to investigating the closing of PCSS by spots of light.…”

Simulation of Current Filaments in Photoconductive Semiconductor Switches

“…Several theories have been proposed to explain lock-on [6][7][8][9][10]. Most theories have assumed that field enhancements lead to avalanche breakdown at unexpectedly low fields to explain the extra carriers.…”

“…Most theories have assumed that field enhancements lead to avalanche breakdown at unexpectedly low fields to explain the extra carriers. For example, one class of theories considers the enhancement at the head of a streamer [8,9].…”