Research On Temperature-Sensitive Electrical Parameters Of Silicon Carbide MOSFET For Junction Temperature Online Monitoring

Junction temperature measurement is an important basis for thermal characterization,reliability research,condition monitoring,and health management for power semiconductor devices.The temperature-sensitive electrical parameter method has a fast response and does not require damage to the package.It is very suitable for online monitoring and is highly expected.As a new generation of wide bandgap semiconductor devices,silicon carbide MOSFET has excellent performance of high voltage,high temperature,high frequency and low loss.It is gradually being widely used in aerospace,power systems and electric vehicles.Compared with traditional silicon-based power devices,the material properties of silicon carbide power devices are quite different,and their temperature-sensitive characteristics will therefore be quite different.This article takes silicon carbide MOSFET as the research object,faces the on-line monitoring technology of junction temperature,and research on the temperature-sensitive electrical parameters of silicon carbide MOSFET and its online application.First,an experimental platform for the temperature-sensitive characteristics of dynamic and static parameters was established,in order to obtain the temperature-sensitive characteristics of the silicon carbide MOSFET.Among them,in order to realize the high-temperature remote connection of the devices in the thermal tank,low-resistance Teflon multi-stranded wire was selected in the static parameter temperature-sensitive characteristic experiment platform,and the flexible printed circuit board with low inductance under the laminated design was selected in the dynamic parameter temperature-sensitive characteristic experiment platform.Combined with theoretical analysis,it is shown that the threshold voltage,transconductance,turn-on gate plateau voltage,switching delay,switching drain-source current change rate and turn-on drain-source voltage change rate are all well linear with junction temperature.And the relationship between on-resistance and junction temperature is approximately quadratic.Secondly,for different application conditions,the influence of the gate forward bias voltage,gate resistance,bus voltage and load current on the temperature-sensitive electrical parameters of the silicon carbide MOSFET is summarized through experimental analysis.Then,online extraction methods of four different temperature-sensitive electrical parameters of gate-source voltage,on-resistance,switching delay and switching rate of change are analyzed.Finally,in order to evaluate the influence of the bias temperature instability on the temperature-sensitive electrical parameters of silicon carbide MOSFET and on the measurement results of junction temperature,an experimental platform for the bias temperature instability of the silicon carbide MOSFET was established.The results show that the influence of negative bias temperature instability is greater than that of positive bias temperature instability,and the on-resistance and junction temperature measurement results are less affected.