Switching-on Delay Jitter Caused by Lateral Distribution of Current Channel of Avalanche Transistor

Abstract

The stability of the avalanche transistor’s (AT’s) switching-on process is essential for its extensive application in power semiconductors. The switching-on process was typically described in one-dimensional terms, overlooking the effects of multi-dimensional structural variations on stability. This paper investigated the influence of the lateral distribution of current channels on the switching-on delay jitter in the AT. The lateral size of the current channel affects the transit time by changing the electron path in the base region, resulting in the switching-on delay jitter of the AT. An analytical formula for the lateral size of the current channel and the switching-on delay jitter has been proposed. The two-dimensional simulation model of the AT gave the distribution of current channels. The model’s accuracy was verified by comparing experimental and simulation data. The experimental data proved that the base transit time was the main component of the switching-on delay. The results show that the switching-on delay jitter can be significantly reduced by adjusting the current channel’s lateral size. In addition, the trigger signal’s characteristics also change the current channel’s lateral distribution and then affect the stability of the switching-on delay, which provides a new perspective for the design and application of ATs.