Drain-to-gate field engineering for improved frequency response of GaN-based HEMTs

We report on a novel approach for designing high-frequency AlGaN/GaN HEMTs based on gate-drain field engineering. This approach uses a drain-connected field controlling electrode (FCE). The devices with gate-to-FCE separation of 0.5–0.7 μm exhibit much smaller frequency behavior degradation with drain bias at least up to 30 V and yield RF gain and output power improvement up to ∼2 times compared to conventional devices. These results show that the FCE is a powerful technique of improving the high-frequency, high power performance of GaN HEMTs at high drain biases.