Reliability of insulating substrates — High temperature power electronics for more electric aircraft

Insulating substrates for high temperature power electronics are in the focus of this paper. The targets were 200°C ambient temperature (base plate) and 300°C junction temperature for the use of silicon carbide devices. DBA and DBC were tested if they are suitable to reach this target. A comparative temperature cycling test under extreme conditions was done. Standard DBC substrates with alumina ceramic withstand only a few cycles. The first idea that higher mean temperatures will increase the temperature cycling capability could not be confirmed. DBA substrates have a very high temperature cycling capability, more than one order of magnitude higher compared to standard DBC. There is a totally different failure mechanism. The surface get rough. There was no optical influence on the die attach quality.