Simulation of Current Filaments in Photoconductive Semiconductor Switches

Abstract

Photoconductive semiconductor switches (PCSS's), such as optically-triggered GaAs switches, have been developed for a variety of applications. Such switches exhibit unique properties as a consequence of lock-on, a phenomenon associated with the bistable switching of these devices. In this paper, lock-on is explained in terms of collective impact ionization. Furthermore, the effect of defects on the performance of these devices is investigated.

Dissipative solitons

“…A review on this work can be found in [200,204]; for later efforts, see, e.g. [206,211,368,369]. However, there is little work where a thorough quantitative comparison between theory and Table 11.…”

“S-shaped” negative differential conductivity of high gain GaAs photoconductive switches

“…The growing dipole domains can be fonned in this activated local region [5,6] if the product of excess carr ier density npe times the characteristic length LE of the illuminated region is larger than 10 12 cm -2 [9] and the localized electric field is in the region of negative differential mobility (NDM). If the growing domain accumulates carr iers and enables the carrier density to exceed nc ;::: :; 10 17 cm-3, the local electrical breakdown can arise because impact ionization is increased [10,11]. The avalanche breakdown can cause an S-shaped NDC [12,13], that is, the avalanche breakdown can complete a transition from N-to S-shaped NDC in this local region, current fil aments will therefore fonn [5].…”

“…1) is in the region of NDM, the second generation growing domains can be fonned. In the growing domains, as soon as the accumulated carrier density exceed nc ;::: :; 10 17 cm -3, the collective impact ionization (Cll) mechanism[10,11] produces rapid avalanching to streamer conditions, thus advancing the filamentary structure. As described above, the rapid avalanching causes and completes the transition from the N-to S-shaped NDC in this activated local region.…”

Continuum models for electrical breakdown in photoconductive semiconductor switches

“…The time-dependent continuum calculations focus on the transport of electrons and holes during electrical breakdown [10]. The calculations focus on kinetic equations for electrons and holes.…”

“…In a previous paper, one such model has been described and used [10]. In this paper, a new continuum model is described.…”