Investigating possibility of lock-on in a photo-conductive semiconductor switch (PCSS) for high power applications

Abstract

Lock-On has been observed in GaAs and InP based Photo-Conductive Semiconductor Switch (PCSS) almost two decades ago. Although numerous attempts have been made so far, conclusive explanation for all related features associated with Lock-On is yet to be made. Since now-a-days, focus has been shifted to wide band gap materials like GaN for developing high power and high voltage PCSS, it is also important to probe the possibility of Lock-On in GaN. This particular thesis developed one-dimensional time dependent simulation model which can be used to investigate the possibility of Lock-On in any materials. First of all, the model has been tested on GaAs and InP based PCSS. The results matches well with experimental data which proves the validity of the model. Band to trap impact ionization and photon recycling are seen to be the dominating forces to Lock-On. Then the model has been extended to GaN. Different scenarios have been tested to find out the most favorable condition that leads to Lock-On. Finally, some high E-field related issues are discussed for future 2D simulations. Different device structures have been proposed and comparative analysis has been done to figure out best solution for reliable and stable device structures for high power application.