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通过商用半导体模拟器MEDICI对700 V 4H-SiC晶闸管开通特性进行了模拟研究。模拟结果表明阳极电压小于100 V时,开通过程符合扩散模型,电压更高时,开通时间随阳极电压升高而迅速下降,符合场开通机制。不同于Si及GaAs晶闸管,SiC晶闸管p型耐压层中浅能级杂质Al使得其开通时间随温度的升高而降低。较厚的基区使得电导调制效应只发生在发射区与基区边界一个范围之内,随着温度的升高,其余部分的载流子数目指数增加,压降指数减小。开通时间随着门极触发电流的加大而逐渐缩短,减小到一定程度时,减小速度明显变缓。
The opening characteristics of a 700 V 4H-SiC thyristor are simulated by MEDICI, a commercial semiconductor simulator. The simulation results show that when the anode voltage is less than 100 V, the opening process accords with the diffusion model. When the voltage is higher, the turn-on time decreases rapidly with the increase of the anode voltage, which accords with the field opening mechanism. Unlike Si and GaAs thyristors, the shallow-level impurity Al in the p-type breakdown region of a SiC thyristor causes its turn-on time to decrease with increasing temperature. The thicker base allows the conductance modulation effect to occur only within a range of the emitter and base boundaries. As the temperature increases, the number of carriers in the rest increases exponentially and the voltage drop index decreases. Turn-on time with the gate trigger current increases and gradually reduced, reduced to a certain extent, reduce the speed significantly slowed down.