The importance of the n-base in p-n-p-n-like structures subjected to dV/dt ramps

Abstract

Prompted by recent experimental results and based upon a critical appraisal of the previous approaches to the topic, a simple yet thorough analysis of physical effects induced in p-n-p-n-like silicon structures by the high rate of the OFF-state forward anode voltage rise (dV/dt) was performed. The importance of n-base parameters in shaping the faulty triggering of thyristors subjected to dV/dt ramps is clearly demonstrated for the first time in the literature. The main implications of the findings for thyristor physics and design are also outlined in this work.

dv/dt induced latching failure in 1200 V/400 A halfbridge IGBT modules

“…where C J~ is the junction capacitance of J2. If the value of dvldt is high enough, then the parasitic thyristor in IGBT structure will be turned on, no matter how is the gate biasing [6] [7] [8] [9]. As soon as IGBT enters latching, it loses the gate-controlled characteristics and the operation mode of IGBT changes from transistor mode to high current thyristor mode.…”

A study of EOS failures in power IGBT modules

“…A further study reveals that a fast rum on of T2 can result in a high dv/dt at point A in fig-ure 1 acting to T1 emitter while its collector is connected with 8OOV biasing. Therefore, the failing process of IGBT module is in such a way that the untested T1 failed at first by latching with a fast turn on of T2, then the tested T2 failed by high power dissipation [4] [SI. X-ray microscope, scanning electric microscope (SEM) and liquid crystal (LC) technique were employed in failure analysis.…”

SEM investigation on IGBT latch-up failure

“…T1 has a p-np-n thyristor-like structure, see figure 3. If the value of dv/dt is high enough, then the parasitic thyistor in IGBT will be turned on, no matter how the gate biasing is [l] [2]. Whenever IGBT enters latching, it loses the gate-controlled characteristics and the operation mode of IGBT changes from transistor mode to high current thyristor mode.…”