Efficacy of ? -Gate in RF Power Performance of Thin GaN Buffer AlGaN/GaN HEMTs

This brief investigates the influence of a ?-shaped gate in extending the microwave performance of a thin GaN buffer AlGaN/GaN HEMT. A well-calibrated simulation deck based on the in-house fabricated thin GaN HEMT demonstrates better reliability when a ?-shaped gate is coupled with a thin GaN buffer. The sample has been investigated under different operating conditions with a specific focus on RF power performance. The modification in the gate architecture results in the enhancement of both the OFF-state breakdown characteristics and thermal reliability for continuous wave (CW) mode operation. The pulsed characteristics of ?-gate demonstrate a lower degree of current slump thereby improving the pulsed mode operation of the devices under test (DUT). This opens up the bottleneck for the GaN HEMT device to be operated at a higher voltage and exhibit higher power densities when benchmarked against their conventional counterparts all the while ensuring modest tradeoffs to the current and device gain metrics. The results presented point toward the possibility of further mitigating the dispersive trapping effects on the RF performance of a GaN HEMT by coupling a ?-shaped gate with a thin GaN buffer.

Automated summary

This study investigates the impact of a ?-shaped gate on the microwave performance of a thin GaN buffer AlGaN/GaN HEMT. A simulation based on an in-house fabricated thin GaN HEMT demonstrates that coupling a ?-shaped gate with a thin GaN buffer improves the reliability of the device. The gate modification enhances the breakdown characteristics and thermal reliability for continuous wave operation, while also improving the pulsed mode operation. This research opens up the possibility of further improving the RF performance of GaN HEMTs by using a ?-shaped gate with a thin GaN buffer to mitigate dispersive trapping effects.