High-efficiency dual-gate InGaAs pseudomorphic HEMTs for high-power amplifiers using single-voltage supply

High-efficiency InGaAs pseudomorphic HEMTs for high-power amplifiers have been developed. To improve power-added efficiency, we developed a new type of dual-gate structure which consists of an enhancement-mode FET and a depletion-mode FET. A highly reliable platinum buried gate was adopted to obtain a Schottky barrier height of 0.8 eV for the enhancement-mode FET. The power-added efficiency of the new FETs is as much as 10% higher than that of single-gate FETs at 1.5 GHz, and +3 V single-voltage operation is possible.