Reliability Improving of Power Semiconductor Discharge Switch by Means of LTJT Technology

Abstract:
The current status of pulse power engineering is connected with development of semiconductor discharge switches that are being used in energy storage devices for pulse power supply of power lasers, accelerators, tokamaks, in magnet punching and other application fields. Total energy in storage devices can reach up to some hundreds MJ. Controllable discharge in such systems demands switches that are able to switch power current pulses by high charging voltages in short time intervals. The most promising semiconductor devices for these applications are reverse switched dynistors (RSD) that proved to be most power and reliable switches in microsecond and sub-millisecond ranges [1]. RSD have low on-state losses and high blocking voltages like thyristors, but in contrast to thyristors they turn on simultaneously and uniform around all active area like power diodes. These RSD properties are used in solid state commutators (RSD-DS) that are designed for operation voltage of some dozens kV and pulse current of some hundreds kA with very high di/dt. But degradation phenomena in press contact interfaces reduce unique switching capability of RSD in multiple repetitive operation mode. This paper presents some methods reliability improvement of semiconductor switches owing to silicon structure optimization and LTJT technology.