Evaluation of BJTS as Closing Switch of Miniaturized Marx Generator

Summary form only given. The micro plasma technology is used in various fields such as processing or chemical analysis of minute material, short-wavelength light source, and plasma function device. The plasmas can be generated by either an electron beam or electric discharge. The pulsed voltage, which is necessary to generate these plasmas, is about 3 kV and required energy is typically in the low 3-10 mJ range. The miniaturized generator has been used to produce these plasmas in the micro-scale area. For such background, the miniaturized Marx generator which has bipolar junction transistors (BJTs) as closing switches has been developed to generate micro plasmas . In the miniaturized Marx generator, BJT´s are operated in avalanche mode to obtain a faster switching speed with ns order. In this paper, three kinds of BJTs which have ditferent collector current each others are evaluated as closing switch. In the experiment, the BJTs are operated in avalanche mode with higher applied voltage (about twice voltage rating) into the between collector and emitter of BJTs. As the result, the closing time of BJTs in the avalanche mode is constant regardless of the value of applied voltage. And, the characteristics of maximum current and maximum repetition rate in the avalanche mode operations of three kinds of BJTs are almost the same.