Investigations on DC conductivity and space charge in silicone gel

In power electronics, the development of new IGBT power modules allow them to switch kV and kA during μs. However, such components need to be cooled and ceramic materials are used as an interface between the electronic devices (the chips) and the cooling. Another key point of the reliability of the packaging of these devices is their encapsulation made of silicone gel to prevent any discharge on the substrate surface and also in the vicinity of the bondings. In order to identify the physical mechanisms involved in these materials, different experiments are performed. The results of conductivity and space charge measurements (using the LIPP method) under HVDC electrical stress at different temperatures are presented and analysed.