低压ZnO压敏电阻大电流冲击老化后晶界电容随时间变化特性的分析

Analysis on the Time Varying Characteristics of Low-Voltage ZnO Varistor's Grain Boundary Capacitance After the High Current Impulse degradation

针对ZnO压敏电阻承受冲击老化后晶界电容随时间变化的问题,基于Block-Model(砖块模型)对影响ZnO压敏电阻晶界电容的参数进行相应分析。通过对压敏电阻样品进行不同次数的8/20波形大电流冲击试验,发现ZnO压敏电阻的晶界电容在冲击后随着时间的增长呈现出先降低后增长的趋势;当冲击次数较少时晶界电容有所降低,而冲击次数较多时晶界电容有所增加,研究表明:晶界电容的变化是由中电场区域生成的深能级施主复合和界面态俘获电子释放过程导致的。

In order to investigate the time varying characteristic of ZnO varistor＇s capacitance alter the high current impulse, Based on the Block Model, the parameters which affect the ZnO varistor＇s capacitance are analyzed. By imposing the different impulse times of 8/20 current on the samples of ZnO varistor, we find that capacitance will decrease first and then increase again. When the impulse time is few, the capacitance takes on a decreasing trend. Besides, when the impact time is excessive, the capacitance takes on an increasing trend. We can draw the conclusion that the change of the capacitance is caused by the recombination of the deep donor-like deflects and the release of the electrons captured by interface states during the middle electric field, the paper has a certain reference value for the research in conductive mechanism of ZnO varistor.