A novel solid state pulsed power module for excimer laser

Abstract

For effective excimer laser pumping high voltage pulses with a pulse duration of 100 ns and energies from a fraction of joules to some 10's of joules are necessary. This energy is deposited via a gas discharge into the laser vessel. The generation of these pulses has traditionally been achieved using thyratron circuits. The limited lifetime and repetition rates of thyratron circuits do not fulfill the requirements of a modern excimer lasers. The current state of the art is to use solid state circuits with insulated gate bipolar transistor (IGBT) switches, high voltage pulse transformer, and pulse compression networks. Due to the many stages, complexity is high and efficiency is moderate. To overcome this limitation a new solid state circuit for excimer laser pumping was developed. The circuit works without magnetic pulse compression. The switch is made by a stack of "off-the-shelf" metal oxide semiconductor field effect transistors (MOSFETs) and SiC diodes. In the presentation the general design and its calculation, diode and switch qualification and test results are presented. An additional emphasis is put on the voltage sharing within the stack and the gate control.