The Role of the Photo-Generated Carrier in Surface Flashover of the GaAs Photoconductive Semiconductor Switch

The development of Gallium arsenide photoconductive semiconductor switch has been hampered by the surface flashover. The surface flashover threshold with the laser excitation is far lower than the one without the laser excitation. In this paper, the phenomena of surface flashover, including the infrared video, flashover spectrum, and the voltage waveforms are presented to research their work mechanism. The dynamic development process of surface flashover is divided into four typical states. Based on the 1-D time domain finite element method, the role of the photo-generated carrier in the surface flashover is analyzed. Our results suggest that the photo-activated charge domain (PACD) will enhance the local electric field and result in the surface flashover occurrence between the electrodes and semiconductors. So the atoms of GaAs semiconductors and electrodes are involved in the surface flashover. According to the PACD theory, the experimental phenomena can be explained reasonably.