Performance of AlGaN/GaN High-Electron Mobility Transistors With AlSiN Passivation

The performance of AlGaN/GaN high-electron mobility transistors that were passivated with AlSiN and SiN and fabricated side by side has been studied. It is found that the AlSiN passivation produced state-of-the-art devices, improving both small- and large-signal performance over the SiN passivation, particularly at higher drain bias. With large-signal excitation at 10 GHz, the effects of second-harmonic termination on the load pull were also studied. Significant improvements in the power-added efficiency were demonstrated.