High-Power Ka-Band Performance of AlInN/GaN HEMT With 9.8-nm-Thin Barrier

We report the first CW Ka-band radio-frequency (RF) power measurements at 35 GHz from a passivated Al
_0.82
In
_0.18
N/GaN high-electron mobility transistor on SiC with 9.8-nm-thin barrier. This device delivered a maximum of 5.8 W/mm with a power-added efficiency of 43.6% biased at V
_DS
= 20 V and 10% I
_DSS
when matched for power at CW. The device was grown by metal-organic chemical vapor deposition with 2.8-¿m source-drain spacing and a gate length of 160 nm. An excellent ohmic contact was obtained with an R
_c
of 0.62 ¿·mm. The maximum extrinsic transconductance was 354 mS/mm with an I
_DSS
of 1197 mA/mm at a V
_GS
of 0 V, an ft of 79 GHz, and an f
_max
of 113.8 GHz.