高电场下固体电介质中陷阱捕获电子动力学

KINETICS OF ELECTRON CAPTURE IN SOLID DIELECTRIC UNDER HIGH ELECTRICAL FIELD

阐述了采用表面电位测试技术研究固体电介质中陷阱捕获电荷载流子的可能性,并利用它分析在高电场作用下电子填充陷阱的动力学特性.根据电场注入载流子机理的不同,作者分别考虑了热发射和碰撞电离脱阱起作用下的一级捕获动力学方程.新的方程能定性地解释在电场作用下介质中陷阱捕获电子的时间特性,该方程的稳态值表示高电场下陷阱捕获电荷量随电场的变化.经实验研究指出,在电场大于1.5×10~8V/m时,介质中陷阱捕获电子数随电场的增强而迅速下降,这是由于自由电子与陷阱中电子发生碰撞电离脱阱的结果,一旦这种碰撞电离脱阱达到一定程度时,介质便发生电击穿.

The kinetic properties of electron capture in solid dielectric under strong electrical field are studied with surface potential measurementin this paper. With respect to the different mechanisms of carrier injection by the field, the authors take thermal emission and impact ionization into account, respectively. The improved first-order capture kinetic equations can explain qualitatively the processes of electron capture and the variation of the steady-state values captured by traps with the fields. It is found that in the range approaching the field of breakdown, the electrons in the conduction band will collide with the trapped, resulting in the trapped electrons detrapping. Once the detrapping reaches a certain value, breakdown occurs.