Study on the destruction mechanism caused by dynamic avalanche in GCTs

• Autores: Wuhua Yang, Cailin Wang, Jing Yang
• Localización: Microelectronics reliability, ISSN 0026-2714, Nº. 92, 2019, págs. 34-41
• Idioma: inglés
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• Resumen

  • Dynamic avalanche is one key factor limiting the safe operating area (SOA) of the gate commutated thyristors (GCTs). The current filament caused by dynamic avalanche and its failure mechanism still need to be studied in depth. In this paper, the relevant theoretical analysis and device simulations are firstly carried out. And a 2-D model describing quantitatively the plasma front velocity is derived to examine the behaviour of the filament. The results show that the avalanche effect at the pn- junction and the hole injection of p-anode region in the GCT can interact with each other during the turn-off, but it does not necessarily lead to the device destruction. However, when the GCT is turned off at high dc-link voltage, the interaction transforms into a positive feedback effect, and the anode-cathode voltage is clamped to a certain value, resulting in the formation of destructive filament. Additionally, the borderline limited by the voltage clamping is given.