Article ID: 21.20240332
With the development of GaN HEMTs, solid state power amplifiers are hopeful to replace the vacuum tube power amplifiers in more and more areas. However, the working voltage and power density of GaN HEMTs are still very low. Transistor stacking is a promising solution to ameliorate this problem. In this letter, we combine a unique high-voltage 0.25 μm GaN-on-SiC technology and stacking topology together and build a high-voltage high-power-density high-gain GaN stacked HEMTs. Our stacked device combines two 20×120 μm GaN HEMTs connected in serial to work at 140 V. The output power and gain of the stacked device are 45.6 dBm and 17 dB, respectively, at 3 GHz and 100 μs pulse width / 10% duty cycle. The power density reaches about 15 W/mm, increased by about 41 % compared with state-of-the-art stacked devices. To the author’s best knowledge, this is the highest power density and highest working voltage among microwave stacked transistors.
