Breakdown Investigation on AlGaN/GaN-HEMT Devices

AlGaN/GaN High Electron Mobility Transistors (HEMTs) are becoming optimum candidates for the fabrication of new high-power and high-frequency devices demanded by future wired and wireless communication applications. In fact, GaN-HEMTs have distinctive electrical and thermal features, like high breakdown electric field, high electron mobility and saturation carrier velocity, high thermal conductivity, etc., make GaN-HEMTs very appealing to increase the performance of actual telecom and defence applications. However, since GaN-HEMTs already adopt sub-micrometer gate geometries, extremely high electric field values can be reached in the device, increasing the risk of fatal breakdown occurrence. In this work we have investigated the breakdown occurrence on GaN-HEMTs, supported by emission and Atomic Force microscopes to analyze failure mechanisms.