N-Polar GaN/AlN MIS-HEMT With $f_{rm MAX}$ of 204 GHz for Ka-Band Applications

摘要

In this letter, we demonstrate the state-of-the-art small-signal performance from N-polar GaN-based metal–insulator–semiconductor high-electron-mobility transistors by using a double-gate-recess technology. The device consists of an AlN/GaN superlattice as a back barrier to reduce alloy scattering. “Funnel” contacts are employed to achieve a low ohmic contact resistance of 0.12 $Omegacdothbox{mm}$. Peak $f_{T}$ and $f_{rm MAX}$ of 82 and 197 GHz, respectively, were obtained for $L_{G} = hbox{112} hbox{nm}$, and that of 95 and 204 GHz, respectively, were obtained for $L_{G} = hbox{75} hbox{nm}$. Large signal measurements for $L_{G} = hbox{112} hbox{nm}$ resulted in an excellent linear transducer power gain of 12 dB at 30 GHz. The merits and the challenges of the technology toward high output power ${P}_{rm out}$ and power-added efficiency have been also discussed.