Failure Analysis of 200V p-GaN HEMT under Unclamped Inductive Switching Conditions
更新：2021-07-21 20:06:01 浏览：216次
Power electronic systems based on Gallium Nitride (GaN) devices are expected to significantly reduce the power losses and increase the power density. This makes GaN power devices very promising for next-generation power electronics, like the applications in electric vehicles, 5G communication, lasers, and renewable energy. However, reliability issues are still an obstacle to the widespread application of p-GaN high electron mobility transistor (HEMT). It is of great significance to study the reliability of p-GaN HEMT to withstand unclamped inductive switching (UIS) shock. This work explains its unique failure mechanism through UIS testing of commercial 200V p-GaN HEMT. During the entire UIS process, the p-GaN HEMT do not consume the energy stored by the load inductance, and the energy transferred from the load inductance makes the electric field of the dielectric under the source field plate (SFP) of the device rise rapidly. This high peak electric field causes the catastrophic breakdown of the passivation layer. The UIS withstanding capability of p-GaN HEMT is inherent to the weakness of its structure. Without p-n junction to support high drain voltage, the GaN HEMTs do not have avalanche capability. Once the drain-source voltage VDS exceeds the critical peak voltage Vpeak, failure occurs. Our investigation provides a comprehensive criterion for the reliability evaluation of p-GaN HEMT.
200V p-GaN HEMT; UIS; failure mechanism; SFP