Research on GaN device gate reliability under power cycling
Gallium nitride(GaN)power devices have been operating under high power density conditions for a long time,and the reliability of their gates has always been the focus of attention,and the degradation of the gates can cause problems such as device mis-conduction and increased conduction loss.A DC power cycling device is designed to accelerate the device aging by means of power cycling.In order to evaluate the reliability of the gate,the threshold voltage(VTH)and the gate capacitance(CGS)are used as the characteristic parameters to design the VTH and CGS monitoring circuits.The temperature characteristics,recovery characteristics,and the degradation of the gate after 100 000 power cycles are investigated experimentally.The results indicate that,as the temperature increases,VTH can drift forward,with a drift amount exceeding 10%,while CGS can remain decoupled from temperature and remains unchanged.After the power cycle,the VTH of the device can recover more than 70%in the first 10 min,and can remain stable after 3 h.CGS do not have recovery characteristics.The characteristic parameters of the two selected GaNs can change in different degrees after 100 000 power cycles,which indicates that the gate can degenerate to some extent after the power cycle.Therefore,it is necessary to consider the degradation of gate performance caused by temperature and thermal stress impacts when designing devices and applications,and optimize the design process to improve the reliability of GaN devices.
GaN devicegate reliabilitypower cyclingthreshold voltagegate capacitanceaccelerated aging