快速关断半导体开关工作特性及实验研究北大核心CSCD

介绍了快速关断半导体开关(DSRD)的工作原理,研究了开关内部的物理过程,分析了系统参数对开关输出特性的影响,研究发现:基区材料的击穿阈值越高、载流子饱和漂移速度越大输出电压上升速率越快;基区高的电场击穿阈值或低的掺杂浓度会增加器件关断时间和最大工作电压;考虑各参数的影响,基于高击穿阈值的DSRD是实现快脉冲输出的理想器件;缩短正向泵浦时间可有效抑制预脉冲,当正向泵浦时间小于200 ns时,输出脉冲波形基本不变;为了获得理想的脉冲前沿,反向电流应在达到峰值时完成对注入电荷的抽取。设计了单前级开关的DSRD泵浦电路,研制了基于DSRD的快脉冲产生系统,输出脉冲前沿约4 ns,电压约8 kV,电压上升速率约2 kV/ns,满足FID开关器件对触发电压的要求。

Study of ultrafast semiconductor opening switch

In this paper,the working principle of drift step recovery diode(DSRD)is introduced.The relation between the device parameters and switching characteristic is revealed by studying the physics processes inside DSRD.The analyses show that the rising rate of output pulse is proportional to the electric field breakdown threshold and saturated drift velocity of carrier.Large breakdown threshold and low doping level are benefitial to improve the maximum operation voltage,but the switching time will be increased also.In general,high breakdown threshold is necessary for DSRD with excellent performance.In addition,for the expanding of the diffusion zone over time,the pre-pulse can be reduced with short pumping time,which is obvious when forward current time is larger than 200 ns.To obtain an ideal pulse front,the injected charge should be exhausted as soon as the backward current just achieves maximum.By a simple pumping circuit,a fast pulse generator based on DSRD with the rise time of about 4 ns and the amplitude of 8 kV was designed,which can be used to trigger the fast ionization diode.