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Aluminium modification as indicator for current filaments under repetitive short-circuit in 650 V IGBTs
Authors & Affiliations
1Madhu-Lakshman Mysore, 1Thomas Basler, 1Josef Lutz, 2Roman Baburske, 2Hans-Joachim Schulze, 2Franz-Josef Niedernostheide
1Chemnitz University of Technology, Chair of Power Electronics, Chemnitz, Germany, Tel: +49 371/531-36091
2Infineon Technologies AG, Neubiberg, Germany
DOI
https://doi.org/10.14311/ISPS.2021.003
Abstract
In this work, an investigation of the top-side aluminium (Al) metallization modification, under repetitive
short-circuit (SC) type I measurements, was carried out for 650 V IGBTs. These measurements were
performed far beyond the safe operating area (SOA). The presence of current density filaments at the
collector side during SC leads to a local temperature increase that reconstructs the emitter metallization
and thus leads to a modification of the top Al surface. Here, the optical microscope was used to observe
the change in emitter surface metallization. For 650 V IGBTs, a uniform Al modification pattern was
observed irrespective of DC-link voltage and SC pulse width, which is in contrast to the results of 1200 V
and 1700 V IGBTs. The computer-aided TCAD simulations were performed using a simplified front-side
IGBT structure to understand the uniform Al modification on all the measured DC-link voltages.
Keywords:
IGBT, short-circuit, current filaments, aluminium modification.