Avalanche Delay and Dynamic Triggering in GaAs-Based S-Diodes Doped With Deep Level Impurity

Abstract

The article is concerned with a detailed switching delay effect exhibited by avalanche S-diodes-superfast GaAs closing switches doped with deep Fe centers. The current and voltage time dependences are simulated in a simplified generator. The dynamic electric field and charge profiles in the structures are calculated. This article describes an impact that Fe capture cross sections of free charge carriers have on delayed switching. The simulation results show that delayed switching is associated with deep center recharging in a double injection mode due to three different processes. There are two different delay mechanisms to be herewith distinguished. A delay effect is experimentally viewed to control the dynamic switching voltage (and the avalanche breakdown voltage) using constant voltage adjustment capability enabled by a triggering circuit supply. The authors demonstrate the way it is possible to adjust the amplitude of current nanosecond pulses in the range of 20-45 A through a lidar transmitter circuit with a semiconductor laser and nonoptimized S-diode. The findings are consistent with the results of numerical simulation.

Suppression of Dynamic Current Leakage in Avalanche S-Diode Switching Circuits

“…The structure of avalanche S-diodes under study is described in detail in [5]. The diodes were fabricated from GaAs structures obtained by vapor-phase epitaxy and doped with a deep Fe acceptor (ionization energy ΔE Fe = 0.5 eV).…”

“…To analyze this effect, the Technology Computer-Aided Design (TCAD) Synopsys (Sentaurus) software was used for calculations. A 1D avalanche S-diode model was developed earlier through hydrodynamic approximation [5]. It relies on the switching of the semiconductor structure through the filament channel [4], the generation of CFDs [8], and the recharging of deep Fe traps [5].…”

“…The most probable mechanism to provide S-diode switching is the collapsing field domains (CFD) [3,4] when switching occurs in local areas (filaments with current density of 1-10 MA/cm 2 ) [5]. With its small-sized current channels, the avalanche S-diode is a miniature device, thus being effectively used in circuits for generating nanosecond current pulses with an amplitude of tens of amperes [5]. In particular, such circuits are required for pumping semiconductor lasers for pulsed LiDARs [6,7].…”

“…In particular, such circuits are required for pumping semiconductor lasers for pulsed LiDARs [6,7]. In such circuits, a pulsed voltage is supplied to the S-diode, resulting in a pre-switching leakage current [5]. Thus, before switching avalanche S-diodes in a dynamic mode, a parasitic current of 0.5-1 A flows through…”

Эффект самоподдержания проводящего состояния в обратносмещенных GaAs-диодах, переключаемых в режиме задержанного лавинного пробоя

“…Возникновение ионизирующих доменов такого типа было впервые предсказано в GaAs-лавинных транзисторах [7] и возможно при сверхвысокой плотности тока (J ∼ 1 MA/cm 2 ), которая достигается вследствие локализации тока в узких каналах [7]. Механизм проводящего состояния в GaAs S-диодах, на протяжении многих лет объясняемый перезарядкой глубоких центров [1,2], в последние годы был пересмотрен и также связан с коллапсирующими доменами [8][9][10].…”