Design for Reliability of SiC Multichip Power Modules: The Effect of Variability

The variability of the temperature-dependent on-state resistance, R
_dsON(T)
, of SiC power MOSFETs can significantly affect the temperature distribution, and, hence, the lifetime of SiC-multi-chip power modules. This work investigates the impact of the R
_dsON
(T) variability on the temperature distribution within a half-bridge power module designed in-house. The actual temperature of the individual dies obtained from IR camera measurements is compared with the virtual junction temperatures measured via temperature sensitive electrical parameter for both the low side and high side topological switches. The experimental results are validated using an electrothermal modeling approach, taking into account the variability of R
_dsON
(T), threshold voltage, and body-diode.