High power, high PAE Q-band sub-10nm barrier thickness AlN/GaN HEMTs

We report a state-of-the-art performance of deep sub-micrometer gate length AlN/GaN High Electron Mobility Transistors using a thick in situ SiN cap layer. With 120nm gate length large-signal load-pull measurements showed a peak power-added-efficiency (PAE) above 45%. To the best of our knowledge, this represents the highest PAE for GaN HEMTs at 40GHz, especially when using a sub-10nm barrier thickness. Furthermore, state-of-the-art peak output power density above 6Wmm(-1) at 40GHz has been achieved in pulsed mode. This is the highest output power ever reported for sub-10nm barrier thickness Q-Band GaN devices. The performance improvement is attributed to the thick in situ SiN cap layer and optimized electron confinement allowing higher voltage operation and lower dispersion under high electric field.