A Study of Switching-Self-Clamping-Mode �SSCM� as an Over-voltage Protection Feature in High Voltage IGBTs

Abstract

In this paper, we study the Switching-Self-Clamping-Mode "SSCM" in high voltage IGBTs in terms of device physics and circuit operation. We present analysis for the HV-IGBT failure mode when operating in SSCM due to an unstable negatively damped system and the design consideration taken into account for avoiding such mode of operation. This will enable the introduction of an over-voltage protection feature during device turn-off to add to the existing over-current protection capability under short circuit conditions.

Investigation and Classification of Short-Circuit Failure Modes Based on Three-Dimensional Safe Operating Area for High-Power IGBT Modules

“…Therefore, the boundary of short-circuit VDC/Vrated-ISC SOA at the medium-ratio region is usually limited by this short-circuit pulse failure. Moreover, an optimized large bipolar current gain βPNP is pointed out that can enable the device to avoid the MOSFET mode and prevent the device from this short-circuit pulse failure [33]. As for the value of βPNP, it is directly related to the device collector-side design, such as the thickness and doping profile of the field-stop layer and p-emitter layer [34][35].…”

Robustness requirements on semiconductors for high power applications

“…Most promising are approaches like self-clamping [3], where the device itself limits the overvoltage (see Fig. 4).…”

Study of layout influence on ruggedness of NPT-IGBT devices by physical modelling

“…7a, the largest t on value (overcurrent event) leads to the collapse of V CE and the device failure. This is the consequence of device entering in latch-up due to the fact that the hole current forward biases the emitter-base junction of the parasitic bipolar transistor [15].…”