过压自保护晶闸管二维电场分析

Two-Dimensional Electrical Field Distribution in Thyristors with Overvoltage Self-Protection

应用有限元法,对两种不同门极结构的过压自保护光控晶闸管的电场分布进行计算机模拟,讨论了电场分布与结构参数的关系及其对过压自保护特性的影响.计算表明,无P^-层晶闸管的穴区最大电场同时受到穴径和穴深的制约,而有p^+层的晶闸管穴径对电场的影响可以忽略,穴区最大电场主要由穴深确定.理论和实验均表明,控制门极的穴径和穴深可以达到控制门极自保护特性的目的.

The electrical field distributions of light-triggered thyristors with overvoltage self-protection for two different gate-structures are calculated in finite element method. The relationship between the field distribution and the geometrical dimensions of thyristors and the effects of geometrical dimensions on overvoltage self-protection characteristics are discussed. Numerical calculation shows that the maximum electrical field in the well region in thyristors without the p+ layer is dependent on both the diameter and the depth of the well, but it is mainly dependent only on the well depth for the thyristor with the p+ layer in the well region. The effect of the diameter on the maximum value of electrical fields may be neglected. Theory and experiments show that, by controlling the diameter and the depth of the well, the breakover voltage of the overvoltage self-protection thyristor can be controlled.