Catastrophic failure and fault-tolerant design of IGBT power electronic converters - an overview <s> 1) High voltage breakdown. <s> In this paper, a new failure mode of punch-through type insulated gate bipolar transistors (PT-IGBTs) at short circuit condition under high voltage operation has been presented. After turning on the IGBTs, this failure mode is characterized as an abrupt destruction mode that takes place several microseconds later under higher collector voltage short circuit conditions. The destruction mechanism of the IGBTs has been investigated using a 2-D and a 3-D device simulation. It is found that the hole-current caused by dynamic avalanche generation at the peripheral region of the device leads to concentrate on a certain point such as the emitter contact edge of the active cells. Subsequently the IGBTs plunge into destruction. This hole-current aggregation depends on geometrical structure of the active cells close to the device peripherals where a parasitic PMOS is formed. The generated hole-current path is varied by the gate voltage and this effect results in degradation of the short circuit capabilities depending on the gate voltages. This model has been evaluated experimentally by making punch-through type IGBTs with a rating current of 200A and the IGBTs have shown enough short circuit capabilities. These devices have successfully been adopted as power devices of invertors for a new hybrid vehicle. <s> BIB001 </s> Catastrophic failure and fault-tolerant design of IGBT power electronic converters - an overview <s> 1) High voltage breakdown. <s> Considering typical conditions of railway traction applications, this paper presents an experimental and simulative analysis of over-current turn-off failure in IGBT devices packaged in parallel within IGBT multichip modules. Extensive experimental analysis is carried out by means of a dedicated test-circuit. Thus, for greater insight, electro-thermal simulations at device level have been carried out. The results show that mismatches in the electro-thermal properties of the IGBT device during transient operation can lead to uneven power dissipation, significantly enhancing the risk of failure. <s> BIB002
High voltage spikes induced by high falling rate of collector current (I C ) and stray inductance can destroy IGBT during turn-off, especially under repetitive spikes  BIB002 . Due to the high turn-off voltage spike, electric field can reach the critical field and break down one or a few IGBT cells first, and lead to high leakage current as well as high local temperature. Subsequently, the heat-flux radially diffuses from the overheated region to the neighboring cells. Collector-emitter voltage (V CE ) collapses after the voltage spike, and then I C rises again. Also, the gate terminal may also fail, which results in gate voltage (V GE ) rising up. High value of V CE and V GE can also lead to short-circuit during turn-on. An abrupt destruction and peak current happen after several microseconds during turn-on. The hole current caused by avalanche generation concentrates on a certain point (usually high-doped p+ region). The destruction point is always located at the edge of the active area close to device's peripheral region BIB001 . Therefore, it is critical to clamp V GE and V CE during switching transients.