Improved surge protection of flip-chip gallium nitride-based HEMTs by metal-semiconductor-metal two-dimensional electron gas varactor

AlGaN/GaN high electron mobility transistor (HEMT) was designed with improved surge protection characteristic through the use of a MSM-2DEG varactor connected in series to the gate of HEMT. Under an ESD surge stress of 1100 V or below, the HEMT incorporating this protection feature doesn´t exhibit any change because the surge stress can be directly blocked by the MSM-2DEG varactor. Furthermore, flip-chip (FC) technology was also used to further improve the thermal performance and reliability of HEMTs. The heat generated in the two-dimensional electron gas (2DEG) channel of HEMT flows directly through the interconnect metal to the submount, and hence improve the thermal conduction. Based on these results, the proposed flip-chip HEMT with MSM-2DEG varactor can effectively improve the surge protection characteristics.